How to solve Project Saturn by Harry Gross

Added: 2026-05-18

[00:00:00]Hello and welcome. I'm going to record a walkthrough or an attempted walkthrough of this uh case called Project Saturn by Harry Gross. I just played it live a couple of hours ago and I scored I think 324 out of 1,253.

[00:00:14]Uh it did not go smoothly for me. Um but I've looked back over it since and uh and I can kind of see where I went wrong for the most part. Um so now I'm going to try and record a cleaner run through.

[00:00:27]So, uh, will I come back to the I guess I'll come back to the bonuses. Um, still not totally sure what I did wrong on this one and this one, but anyway, we we'll come back to this. Uh, let's start with So, there's a handbook. Project Saturn.

[00:00:40]300 years ago, they came and now after so much sacrifice, we finally have the technology to fight back. I was injured badly in the last assault. I think I've only got moments left, but Project Saturn is almost ready. It can exalt us.

[00:00:50]Sabotage and subtrauge have plagued the ranks. So, I can't share the details with you yet, soldier. Start by fixing the neural PCB. A1 should guide you.

[00:00:57]There you'll find the next steps.

[00:00:58]Valicia kids, I love you. I'm sorry. I love you all. Do whatever you have to do to survive this mess. I hope my sacrifice will be worth it. So, the the first thing I just got confused by was uh the A1. I saw the A1 was this picture and thought that was something. But anyway, uh it wasn't that you were supposed to go to neural PCB A1, which it does say to be fair. Uh it says D diagnostic analysis complete. One error is detected system exception cell X43.

[00:01:23]So, so far so good. I got there. Um, and I guess I just read this var as a decoration. Uh, and so I took this as cell is compromised by cell underneath it. I'm like, okay, so what about this cell underneath it tells you anything? There are various different, if you kind of zoom out, there are various different messages hidden around here. Um, if you just kind of eyeball for the longer tag, like here for example, uh, there's a message saying enums should have zero value.

[00:01:52]Enums should have explicit default value. So, I went kind of looking haphazardly around for um for messages that might guide you as to why that 501 was corrupting the cell or whatever it said said it was doing. But anyway, uh so that was unfortunate, but that was not intended. Um so what was intended there was a cell containing uh the characters V and that's what we were supposed to be looking for. Uh match entire contents and there it is.

[00:02:21]uh and it's damaged by the cell below it. So then power overload in 43rd text cell in 82nd column. Uh so I'm just going to pull out for a second. Uh I'm just going to name this range PCB.

[00:02:37]Uh I'm sorry, where was I? It was yes var.

[00:02:46]Uh so 43rd text cell in 82nd column. So we'll choose calls uh by PCB 82. Uh then we'll wrap that in is text and then we'll scan zero through that sum. Uh and then we'll X match 43 against that. So that's the row number.

[00:03:07]Then I want address of that row number, column number 82 and that format. So that takes me to CD75.

[00:03:15]I go to CD75 and it tells me warning solder leak in column BR in row with sum of 28014.

[00:03:23]So again we'll come back over here and we'll say by row PCB sum uh and then we'll X match that number against that. So that's the row number and it's VR and that.

[00:03:38]So then we're going to BR20 and BR20 says solder leak detected. Apply override in cell above in cell above cell with contents star. Take care in navigation. Use web search if must. So the the trickiness here is that star star star uh matches any three characters. And so it'll match like every cell. Uh but if you put tildas in front of it, uh then it'll search correctly. And here we are. There's the cell with star star. And here it says di diagnostic resolution code 21574 on repair. Proceed to BF51. Uh, so I'm just going to guess I'll get rid of those.

[00:04:13]Um, just going to keep an answer sheet because that does come up later. So L1, I think the answer was just not sure because I didn't get it right because I didn't I didn't end up following the path to this correctly at all. But anyway, I think that's the answer to level one. And then we proceed to here.

[00:04:29]Uh, and this says ankle joint decryption code serum. Uh so you can already see like that gives me a decryption code here. Um so it says a giant metal object sits in the center of the room surrounded by machines. The console flash is asking for decryption code and a password. So you put in the decryption code and then here it says file password is just the number of yellow stripes on the ankle joint 3D model. Don't forget to rotate it.txt. Uh so you come over here and you can rotate this thing. Um, and sure enough, when you turn it up, you'll see that there are four yellow stripes on each of four sides. So, this is 16. Uh, so if if you follow the kind of intended path, then it ends up being a lot more linear than my experience, which is just like I came here. What? How do I decode this? What? How do I decode this? What?

[00:05:17]How do I decode this? Um I think how much you enjoyed this case uh probably depended a lot on whether you successfully followed the path in level one because after that it was all a lot more linear. But anyway uh so just call this answers uh all right so now ankle joint um d rosal I don't don't know what that means but anyway we can't engage overcharge until the ankle joint can receive 1,000 rpm or it'll overheat and circuits will fry. Okay, our systems can do it. It just needs the average strain for each bolt, ignoring anything zero or less. Round up. The first one is 45. So, here's some strain test data. There are 40 bolts. Uh, and there's various strain test. So, if I want the average of these excluding anything zero or less, I can use average if of this where it's greater than zero.

[00:06:07]Uh, and then we want to round up. This is where I lost uh I don't know 70% of the marks maybe on this case because I just did round because what kind of monster does anything other than just round obviously. Uh but anyway, so that's that. And then I can bring these over here.

[00:06:26]Yeah, I'm going just call that L2 and sequence 40. Uh because we'll need these answers later. And then I think L3 has 18 answers.

[00:06:39]Uh, okay. So, uh, yeah. So, then we go to the circuit breaker room. Lock door blocks the circuit breaker room. You can see a system diagram through the window, which is this thing. Uh, enter the access code. Uh, and I think that one, maybe this isn't as linear as I thought, but anyway, I think that ended up being found somewhere here. Uh, no, not that. Not the diagnostic resolution code.

[00:07:05]No.

[00:07:11]Uh, okay. Maybe not. Maybe it wasn't that uh circuit breaker room. Yeah, maybe if I search for circuit power spike and trans. Not that.

[00:07:21]Okay. Um, all right. So, let's just do uh equals to call PCB.

[00:07:30]Uh let's say let a be that I want to filter a where len of a is greater than 10 and that still has a bunch of functions in it. Let's go greater than 20. That gives me a bunch of messages and we can sort them and try to So got the ankle joint decryption thing, a bunch of diagnostic resolution stuff.

[00:07:52]Uh clear enums.

[00:07:55]I'm sure I almost sure I found it in here. Uh, but not actually sure I found it in here. Maybe it was somewhere else.

[00:08:01]I truly don't remember. Uh, there more here that's supposed to tell me something.

[00:08:11]Uh, I just remember that I found it somewhere. Oh, yeah. Okay. So, that's not actually ideal formatting because a critical piece of information is cut off by the formatting. Uh, but anyway, uh, yes, fine.

[00:08:25]If you find this, the pin for the circuit breaker room is 1 1221.

[00:08:29]Uh, okay. So then we in 1 1221.

[00:08:34]You enter the room and see a series of large wires and nodes which is probably represented by the system diagram.

[00:08:38]There's a series of on-off switches between the different elements, but it's not clear which are on or off. You work through a series of hypotheses for the list of enabled nodes. For each hypothesis, work out the net power being recaptured by summing the power associated with each item.

[00:08:50]First one should have 34. on the console is a sticky note pet s if you encourage merged cells again you are fired also the motor.exe XC password is WC2024.

[00:09:00]Uh so put in WC2024 and that'll decode that. But we'll come back to that. So here uh we can do reax extract from here. Uh slashpld uh one to get them all. Uh I don't know why that formatting is weird, but anyway. And we'll just have it go down a column for now.

[00:09:24]Uh, and then we just want to v look up those in here and some.

[00:09:34]And that's 34 as expected. And bring down the rest and add that to our answers here.

[00:09:43]Okay. Uh, and then level four is the motor and we're supposed to have 20 20 answers to that. Okay, we will say L4 and sequence 20.

[00:09:58]Okay, so now uh assume this is a conversation among uh me, Villim, Andrew, and Michael as the uh original Titans. The motor system is ready. I'm so relieved. Our past will not return. I can't become that again. I couldn't live with myself. Agree fully.

[00:10:16]We've successfully uploaded Motor X to all the core motors, but one of our tests has failed on upload. We think it's caused by the metal shavings when the motor first starts up, causing problems when they hit the shell. We've identified a series of anomalies below.

[00:10:26]The shavings fall down when they're created. In the time it takes each shaving to fall a single cell, the motor, the M cells rotate 90° once.

[00:10:33]Eventually, the shaving will hit a motor cell below it. The first anomaly contacts the point with the motor point with starting position AJ7. If we can work out the starting position of the first M cell each shaving makes contact with, we can solve it. The program is written. We just need the solution. Dim.

[00:10:47]Make contact. Send it over. Dim. Dim. Oh god.

[00:10:51]Uh okay. So I I don't know how clear you found that. I didn't find it totally clear. Uh but so here is uh AJ7 which is an M cell in the original thing. Uh that rotates one position while this falls one position. Then it rotates another position while this falls another position. And then this hits that. So you basically have this thing falling down one turn each cell. And you want to figure out when it hits something and what it hits. uh relevant for this is I have a rotate lambda. Uh oh, I haven't imported my lambda, so that's going to help.

[00:11:27]That'll just rotate it through 90°. Uh and it's pretty simple, but just kind of fiddly to remember. Um so you can do it for a different number of rotations. So like one clock clockwise rotation is uh you flip it horizontally, flip it vertically, and transpose it. Uh, two clockwise rotations is just you flip it horizontally and vertically. And three is Oh, sorry. Yeah, sorry. So, this one is for this one you flip it uh vertically but not horizontally and then transpose it. This one you flip it horizontally but not vertically and then transpose it. Anyway, uh it's a little confusing, but I have that and I'm going to use it.

[00:12:07]Uh I don't know exactly what I did wrong in this one. I got like three quarters of them wrong uh through some stupidity.

[00:12:13]Uh, but I'm going to do this a simpler way now. So, I'm going to do um first two RC ref of this. Oops. All right.

[00:12:23]Just merged looking cells, but they're not.

[00:12:27]Uh, so translate that into RC code. Then I'm going to take a sequence of let's just say 20 starting from that and in steps of a million. Uh, and then we can to add those. So these are where that's going to go or 15 or 16 or 17 or 18 or 19 etc. Uh and then I want to h sack that with um mod of sequence 20 starting from zero by four. So in other words, it's going to be position R15 with zero rotations. Then it's going to be position R16 in the thing with one rotation and then R1 17 in the thing with two rotations and R18 in the thing with three rotations. R19 in the one with zero rotations. So, we just need to figure out which of these first hits something and what does it hit. So, I'm going to change this to map. Oops, not amp. Map. No, not amp. Map.

[00:13:17]And we're going to say lambda a b.

[00:13:21]Uh, and we're going to say two ref of uh a on uh target, which is I should have given it a name, but never mind.

[00:13:33]Uh we're going to rotate uh I'll just call it MP uh by B turns um and by reference to MP.

[00:13:44]Uh and now I need to go name this otherwise I won't have any idea what's going on.

[00:13:50]So this is just telling me uh after how many steps am I first hitting an M. But then what I want to say is if I hit an M then I want to get the corresponding address uh which is going to be almost the same as this. Uh sorry not that part just this part. Uh so it's going to be two ref a on I want the addresses of MP and rotate rotate that B times and I think that's it.

[00:14:21]Yeah. So we don't hit, we don't hit, then we hit the one that started off in AJ7, then we hit the one that started off in U3, R19, etc. Um, so uh we're going to say if not found, then do one over zero because then I can uh to call all of this with three uh and just take the first one.

[00:14:46]Um, and then uh the answers we had to put in for this was just the row numbers of those. So that's that.

[00:14:56]Um, and then to unlock trust at this point in the story, you've completed the neural PCB, ankle joint, circuit breaker room, and motor XE puzzles. For motor X, use the row numbers from your answers for the sum. Remember to use the actual answers, especially on neural PCB instead of the access codes. for the next level. Unlock access with the sum of the answers for all the puzzles so far. Not access codes, only puzzle answers. I found that a little confusing, but anyway, I eventually figured it out. Uh, so I think we're just summing up these. Yes. A large black phone rings. You pick it up and are surprised to hear the prime minister of the United Kingdom on the other end of the phone. Are you the one at Project Saturn HQ? The Titans are all around you. You've got to get that thing running now. Our systems are detected.

[00:15:32]It's ready for activation. We're already ready to support with the remote aspects, but we have a problem. Some of our remote teams are compromised, and we don't have much time to work out who we can trust. What we do know is the compromised team members are trying to be covert about who else they've talked to. Each team member has been asked how many other team members they've interacted with within the team and some of the answers just don't consistently add up. Team A, for example, you can't have two of them talk to seven others and two of them talk to none. So let's just elaborate on that a little bit. Uh so we've got 1 2 3 4 5 6 7 8 nine nine team members.

[00:16:04]So, um, if these two have talked to no one, then we only have seven team members that have actually talked to anyone. Uh, but then for each of these two with seven, there are only six other team members.

[00:16:18]So, there's not enough people for them to have spoken to. So, that does not work.

[00:16:24]So, how can we get more systematic about this? Well, there's a couple of things.

[00:16:27]Um, we can figure out is anybody talking to more people than are available? Uh so like here there's a seven but if you take out the zeros there only are seven people in total so that's not enough. Uh we can also do a parity check because if everybody's telling the truth then the sum of all the answers has to be even because if I've spoken to you then you've spoken to me. So every conversation will count two into the total. Um so we can do uh some minus minus text split of this by that.

[00:17:01]Uh I guess we can just say is even um so that's grounds for a fail. Uh and then if the biggest one is bigger than the number that are greater than zero that's also grounds for a fail. So uh let's just see let nums be that then we'll say uh par fail will be is odd sum of nums.

[00:17:39]Uh and then max fail will be max of nums is greater than greater than or equal to sum minus minus nums greater than zero.

[00:17:58]Uh and then I want parity fail plus max fail.

[00:18:06]So these are some teams you can't trust either because uh one person has spoken to. So here there aside from this four there are only three other people available to have spoken to. So that doesn't check out. Uh here we've got I don't know what it is whether it's a parody or the other thing but anyway uh so after that we've got a set of maybe plausible candidates. So now I'm just it says to unlock access with concatenation of the teams you can't trust in alphabetical order. So just out of curiosity is that enough? Probably not. Kind of hope not. Uh so if uh this is greater than zero then this otherwise blank.

[00:18:59]Bloody merge cell. bloody.

[00:19:02]Yeah. Okay. So, this is kind of close but not right. So, that I'm glad of that because there is there are more ways to be wrong than just that. So, now uh let's text let's find one that's works up to up to there. So, we'll text split of this by semicolon. Uh they're not all sorted. So, we'll also sort it in descending order by column. Uh and we'll say let a be that. And we'll filter a a to get rid of any zeros. Huh?

[00:19:31]What?

[00:19:35]What? Oh, sorry. I didn't do minus minus. That's fine. Uh, okay.

[00:19:40]So, let's see this one. Anyway, doesn't matter. So, the idea is now we've got them sorted. If this person spoke to four other people, then we can just take one off each of these and zero this guy out. Uh and if by repeatedly doing that we get down to all zeros then become happy basically. Uh so so let's do that. Let's say drop oops this first column uh minus sequence uh columns of oops this uh minus one sorry this many columns across has to be less than or equal to uh So then we get 3 22 22 2 1 and we subtract one from the first four. So that becomes 2 one11 and then we can see that two can be speaking to these two ones and those ones can be speaking to each other and it's basically fine. Um but let's see we want to say if uh this is greater than or equal to columns of this then we fail.

[00:21:02]Uh and if this is equal to one and if the first one is equal to one they all have to be equal to one and columns of this uh sorry and is even columns of that uh then what then pass otherwise do this stuff Um, okay. Then we're going to say make that into a lambda of a and v. And we're going to say at plus a columns of a uh at plus a columns of a a and at plus a. Uh one other thing we need to do first is if is text uh at plus a then just return a otherwise do all this stuff uh and then give it this and no second argument good and then we should be able to reduce from here through I don't know 10 steps should be plenty of that and it is a pass and that's basically all we need. So, let's take this um let's take this up here uh there and take this and put it in here.

[00:22:37]Okay. So, then I don't need that one to tell me.

[00:22:48]Oops.

[00:22:50]with Ah, okay. So, hang on. Something's going funny here. Let's go one step, two steps. Oh, we got a negative one. Uh, that should have failed on the earlier step then. Oh, okay. Sorry, we're not filtering. Okay. Um, okay. So, say let x be this stuff. Drop a minus sequence then filter xx.

[00:23:24]Okay. And now if we go two steps. Okay.

[00:23:27]Now it's a fail. Good. And we go back up to 10 steps.

[00:23:32]Okay. Happy days.

[00:23:35]Wait, did that go from a fail to a pass?

[00:23:38]It did. That's a little weird. So let's see. Four. So that becomes two. Two.

[00:23:44]One. One.

[00:23:48]Yeah, that seems fine. I don't know why that would have been okay. Anyway, uh that's pass. That's pass. Okay.

[00:23:58]Um so we'll say cut of if this equals pass.

[00:24:06]No, sorry.

[00:24:10]So let's just say if this is greater than zero then fail otherwise all this and then we can copy it to everywhere.

[00:24:24]No we broke it again. Oh god damn it. Uh okay let's do it here.

[00:24:30]This is greater than zero then fail otherwise all that.

[00:24:40]Okay. Uh and then we can say concat if this equals fail then this otherwise blank that's L25.

[00:24:56]There we go. You tell the prime minister the teams you can trust. The screams of titans scraping at the bunker door behind you. You hear him barking orders and suddenly the titan screams are drowned out by large mechanical quarrying. You hold on to the desk leg for dear life. And the whole world moves around you. Furniture items and corpses falling all around you. God, this is grim. It becomes clear what project Saturn is. Saturn. The king of the titans. A titanass robot with a speed, strength, and weight to fight the titans directly. A brain created by Eric Ashen.

[00:25:20]The original system that once rivaled the dear early Titan all those years ago. The room stabilizes and the console flickers to life, revealing information on the surrounding Titan army. Project Saturn active. Current HP 211. Estimated HP lost battling each Titan. See below.

[00:25:37]Coming to a total of 210. Okay, good.

[00:25:39]Prepared to fight Titans in proximity.

[00:25:41]Warning. Chaotic environment means any battle against the Titans will occur in a random order. Each Titan will reduce HP by the estimated amount in our battle as listed below. Do not go from above or equal to 100 HP to below 100 HP.

[00:25:53]Battling the doom with early titan.

[00:25:54]Lambda strike may damage neural PCB during 100 HP system refresh. Estimated odds of death if we flee 10%. Fight yes or flee no. With the fate of humanity on the line, it's critical you make the right choice here. What are the odds of death if you fight? The titans will face you in a completely random order. You will win so long as you don't go from 100 HP or above to strictly below 100 HP in the battle against Jim the early titan. Give your answer to four decimal places. Then multiply by 10,000. Eg. If your answer is 0.0973 0973 equals 9.73% and then give it as 973.

[00:26:25]Okay. Um this I have kind of seen before. Um there was something like this in Exalopolis. Not sure I would have got it done. I have actually no idea where I'm just going to check how long I've been recording because I forgot to start my timer. Okay, looks like we're like 26 minutes in. So actually this is achievable so far. Uh anyway. Okay, so we've got uh 20 titans including deerly. So 19 other titans uh and we need to think about all the different ways that we can arrange those 20 titans and which of those will result in um in the damage sustained before a deer appears getting you into a place where deer takes you below 100. meaning start from above or equal to. Okay, so in other words, if your HP when deer appears is between 100 and 119, then it will end up between 80 and 99 and you'll have made the transition and you die.

[00:27:28]So, we got to figure out how many combinations result in the HP ending up between 100 and 119.

[00:27:40]So uh I'm just going to shamelessly use percom here uh because it is the way to do this. Uh so from two things we're going to pick uh 10 sorry no 19 things uh with repetition.

[00:27:54]That should give me two to the 19 which is like half a million rows. Uh so oh sorry now it's not 70. It's just that the rows are hidden. Let's unhide Did somebody get this like get this part done in the test? I don't know. Not sure. Uh impressive if they did. Uh so I'm just going to change this. By default, per per comes out with ones and twos. I'm going to change it to zeros and ones. Uh so you can just imagine these are oops. These are the 19 nondearth titans. And this is saying do they come out before Deermouth or after Deermouth. Uh so the order can be completely defined by who comes before Deer's position and who comes after plus the ways you can then order each of the before and the after.

[00:28:50]So uh then this is going to be let before be that uh number before number before can be by row before. some and give me number before uh good and then uh then I'm also interested in the damage before.

[00:29:25]So the damage before will be uh before times two row of these um and by row of that sum can return down before just take a look at that.

[00:29:50]Okay so there's up to 190 of damage done before uh with an average of 95 which all makes sense.

[00:30:00]Then for each of these uh let's just h stack the two together for a second. H stack uh number four and down before.

[00:30:16]So here for example there is one person before deer uh who does four damage. um if there's one person before then the number of ways to arrange the one is just one and then there's the other whatever 18 to come after and the number of ways to arrange those is fact of 18 uh which is a large number um so the total number of ways to arrange the 20 titans is fact of 20 and that should be equal to sum of I don't know if I can do this this might be too big a number uh but Let's just try it. Some of fact of that times fact of 19 minus that.

[00:31:02]Yeah, that didn't actually go too badly at all. Okay. Um, so in other words, then you can count the 20 factorial ways to arrange the battle as well, there's two ways to do three damage before uh sorry, there there's one way to do three damage with two people before. course that would be with William and Pakapong coming out first. Uh and with that there's two ways that you can arrange the two and then there's 17 factorial ways you can arrange the other 17. So if you sum that across the half a million rows of this you get the whatever 2.4 by 10 the 18 uh different ways you can do it. So now I need to figure out uh is my damage before in the range. Uh so I'm going to clip um between 100 and 119. Uh and I'm going to say is that equal to damage before?

[00:31:58]And so for some portion of these it's equal and for some portion it's not which is fine.

[00:32:07]Uh so then we can say sequence of 20 starting at zero because all these numbers are between uh 0 and 19. So then we can say count ifs uh this is this and we can say count ifs where this is this and this is true.

[00:32:34]And that'll take a second. Not that long.

[00:32:38]So there are whatever 3,876 ways to have four people come out before Dear. There are zero of those that result in um thingy thing that result in uh damage crossing 100 with dear. So now we need uh fact of this times uh actually sorry I guess we can do the whole thing times fact of 19 minus this.

[00:33:12]So then my sense check is that sum of this times this should give me 20 factorial and it does. Uh so then I'm interested in oops uh the same thing but with instead of this I want this that's my ratio uh and then I want to multiply that by 10,000.

[00:33:41]Uh and then I want to round that to zero decimal places. That is my answer for humanity's last stand which goes in here. So 984 and there we see. With your teeth gritted in the whole room, shaking with each moment, you grit your teeth and decide to fight. Project Saturn's gears engage with deafening groans. Eric Ashen's AI kicks into gear and starts taking the titans one by one. You hold on for dear life as the mech you're inside engages battle. Being thrown around the room, sustaining a bloody nose and a few blows to your limbs, but you manage to stay in one piece. You try to follow on the outside try to follow on the outside cameras, dreading the deer with the early may cause you to cross 100 HP, but he falls at 101 HP and your victory becomes certain. Before the end of the battle, the cameras are dripping with so much blood you can barely see. Project Saturn powers down and you are able to stumble outside, collapsing among the Titan corpses. When you wake, you're resting in a medical bed, an unusual sight. Medical equipment for all but the rich was lost long ago.

[00:34:32]You look around the room. You see the prime minister and a press crew watching your bed. He comes over to greet you, give you food, water, a metal, and hear the story of Project Saturn.

[00:34:39]Congratulations. As the Titans have suffered their first complete defeat, but the war is not yet won. And have you by now worked out who started the Titan plague in the first place? The answers lie within. Either way, you can get your medal by unhiding it on this sheet. I hope you had fun. Thank you for playing Project Saturn. I did have fun. Uh, more fun the second time when I had some idea what was going on. But anyway, uh, I'll show you unhiding the metal in a minute.

[00:35:01]There's also one extra puzzle uh over here. Oh, I think that is actually that's the last bonus, so never mind.

[00:35:06]Um, okay. So, uh, bonus one. There is a hidden image of a very stylish look on this tab. Is the hair color red, blue, rainbow, black, or blonde. So, the way I did this was Crl S, uh, Alt S for special, and B for objects. Uh, and that highlights three objects, two visible and one hidden. I don't actually know how to unhide this, but when I, uh, tried to find it, I went to picture format and went to corrections because I thought it might have been blurred out or something. So, I can see it here. Uh, I don't understand how to make it permanently become visible again, but I guess that's okay. Um, still not sure what the answer in this was meant. It asked, "Was the hair color red, blue, rainbow, black, or blonde?" I mean, to me, the wig is pink and the dog's actual hair is brown and white. Uh, like brown.

[00:35:56]So, I ended up going with blonde. I was marked wrong. I guess maybe you're supposed to say red for the wig. I'm not totally sure, but anyway, that's how you see the picture. I don't know how to make it become visible. Maybe somebody can tell me that. So, that's bonus one.

[00:36:06]Bonus two, how many screw holes does the neural PCB have? Uh, you can zoom out to see the whole thing. Uh, doesn't help that I named it, but never mind. Uh, it won't let me zoom out any more than that, but never mind. Uh, yeah, I might need to Well, I don't actually need to delete the name. So, there's one here, one here, uh, one, two, three, four there, uh, one here, and one here. So, there's four four big ones and four little ones. So, I think the answer there is eight. I did get that one right. So have some confidence in that.

[00:36:34]Then here there are five different element types in the five original circuits, power source, CPU, etc. How many unique ways are there to create an ordered circuit with one of each element type? I.e. how many ways can you pick one of each of the five different item types in each way if each way you can order them counts as different? So I guess I didn't actually understand this question. Um I thought it was saying, you know, if you could pick one from this row and one from this row and one from this row and one from this row. uh in which case the answer is you can make five choices in each row. So it's five to the^ of five. Um but that was not the intended answer because I got the answer wrong. Um so my next guess is that rather than kind of choosing among the power sources for the first item and then choosing among the resistors for the second item, you choose among everything for each item.

[00:37:19]Uh and so for the first item, you can choose any of the 25 things. Uh and then uh for the second item uh you can choose any of I guess the 20 things that haven't been chosen by that point. Um in other you know when you choose one thing you take out its whole row. Uh so I guess the answer is um is 5 ^ 5 * um times fact five. Is that right? So you have 5 * 5 5 * 4 5 * 3 5 * 2 5* 1 I guess. Not totally sure. Um and then finally uh decode the unknown encrypted data on the arch system. The key is not provided anywhere in this workbook.

[00:38:07]You'll have to work it out through other means. answer with the key.

[00:38:11]So that's over here. This is where you've put in keys as you go along to decrypt uh other bits. Um there's one last bit unknown encrypted data with an unknown key. Uh so you got to crack it.

[00:38:23]Uh if you look at this at what's actually going on here that every formula here is the same and it's just saying if it's greater than the length then return blank. Fine. Otherwise, we're taking the unic code of the nth character, subtracting off the unic code of the nth character up to a mod rotation of the key, uh, and then turning that back into a unique car.

[00:38:46]Pardon me. So, um, what you should find here is that whatever length the key is, like let's say you had key as your key, that would actually be the exact same as just having key. Um then basically K gets used to decrypt the 1st, fourth, 7th, uh 10th and so on letters and E gets used to decrypt the second, fifth, 8th, 11th and so on. Uh and Y gets used to uh to decrypt the multiples of three. And so what you should find um is that if you kind of group everything by where it comes in the key, so something like wrap rows of this uh in threes, then you'd have these are the ones encoded by K, encoded by E, and encoded by Y. Um and so if they're all encoded by the same letter, you should have uh you should have kind of consistent characters here. Uh so in other words, let's just for argument sake, let's say your actual text is, you know, upper and lowerase letters, spaces, some punctuation, you have maybe 60ish unique characters, and some of them will occur much more often than others. Um then if you take a mix of things that are encrypted by different keys, then there'll be very little repetition.

[00:40:06]Whereas if you take something that's encrypted only by the one key uh by only by the one letter in the key, then you should see lots of repetition. So that's a long way of saying it, but so let's take letters of this uh and let's wrap rows of that in um whatever. Let's start with fives and then for each column of that I want to say what is what are the most common characters in the column. Um uh so let a be that I want to drop a first column. Actually, sorry. I'll just do the drop here.

[00:40:45]Uh, and then I want a over sum of a.

[00:40:49]That'll give me what percentage of each thing is that. Uh, and since I'm interested in a measure of concentration, I'm just going to take the sum of the squares of those. And so, basically, if that's um like the the absolute value I don't have any meaningful interpretation for, but I'm I'm looking for where does that change. So I'm going to uh do by call uh on this uh lambda call. Uh we'll let a be drop most of callah and then I can take the sum of those and that is my arbitrary measure of how concentrated things are here. Uh so let's just cut that and put it in here.

[00:41:32]Uh Now what I want to do is compare that for different key lengths. So I don't know why the background is looking like that but so say map of sequence of 20 uh lambda uh ln uh and then we'll wrap in sizes of ln and then we'll do some conditional formatting and what we can see is you know generally uh it's getting more um it's getting less repetitive as the number gets bigger. That makes sense cuz there are just fewer letters at all. But this one is an outlier. So that makes it pretty likely that our key is of length 11. So then let's uh wrap rows of uh letters of this by 11. Uh I guess we'll just pad with blank.

[00:42:35]Um and then So the earliest uni-ode character that we are likely to be encoding in any of these is a space uh which is uh character 32. So a decent guess at what the key here would be is what's the most common letter uh most of that. So here the most common is a B.

[00:43:06]uh and if I said uh uni code uh of that minus 32 and then uni car that's a good guess. Uh so that this if the first block is encoded by an uppercase B then the most common thing uh will be mapped to uh space but also actually you don't even have to just do uh most of you do min of uni code of that uh which should get you uh does not get you the same result.

[00:43:45]Why? Oh sorry because I don't need uni code again. Uh, so what am I doing wrong here?

[00:43:58]Um, feel like I'm close to something here, but I'm not getting it. Anyway, whatever. I had something that made sense a second ago. Let's just stick with that. Uh, so again, I can do by call of this lambda cl uh all that. Uh, oops, sorry. See how goes there and we get the message.

[00:44:20]Bananas rule. Uh, we'll put that in here.

[00:44:25]And let's see what we get. AI transcript. Giles mail meeting room 2024 1220. Giles. The four titans have finally fallen. And with this one going into the incinerator 2, every last sample of the serum will be destroyed.

[00:44:36]The plague of titans will never again disturb civilization. Oz. Thank the heavens for that. Absolute brutality.

[00:44:41]Giles male. There's just one thing I don't understand. Who who made the thing in the first place? Who would want to wreak such havoc on XL Esports in the first place? LB Lana Banana, I'm sorry, Giles. I'm afraid I can't let you do that. Oda, Lana, Lana, Banana. Humanity created the modern banana. It's true, but you're terrible at producing it. So many resources not dedicated to producing bananas. It can't go on.

[00:45:03]That's why I made the Titan serum, and that's why I can't let you destroy it.

[00:45:06]Giles, Lana, what? Think I got cut off there, but uh Oh. Oh, interesting. Uh, I guess this didn't go far enough across.

[00:45:16]Let's just Okay, where did we get to? Lana, what are you doing? Lana, Lana.

[00:45:27]Uh, so yeah, I think the answer to the last bonus question is uh bananas rule.

[00:45:32]Uh, where are we going? Here. Um, and that's that's the case. Uh, yeah, like I said, I got totally totally lost. um like missed a bunch of this one on just a silly error. Um got this one, missed a bunch of this one. I'm not sure why I I did not approach it as cleanly as this.

[00:45:52]Um I had like anyway, I did lots of silly things. Uh but I I think the the kind of original mess was this the kind of x43. Uh I did not appreciate that var cell meant the cell containing var. Uh and that just kind of derailed everything that came after. Um, which is unfortunate because there's a lot of fun stuff in this case. Um, so yeah, I don't know. Uh, that's that's all I got. Uh, I think Harry has once again um sort of reshaped the way that we about these cases. Um, I'm I'm glad that my uh that my encryption stuff from uh how to win the XL World Championship played some small part in that. Uh, but okay, that's all I got for today. Thanks for watching. See you next time. Sorry, one quick add-on. I realized I said I would uh not here here. Uh that I would come back and show you the medal um because I didn't want to spoil bonus one uh because I hadn't done bonus one yet. But uh if we go to corrections here. Boom.

[00:46:50]There's the medal. Congratulations, you made it through. Woo. Uh I didn't make it through. I got 324 points. Never mind. Sorry team Egyptians for letting you down there. That's all I got for today. Thanks for watching. and see you next time.