Behind the Scenes: Stack Design, Build and Test Process, Cold Hard Cash and the Day of

This is part 8 of a 10-part series.

Before I talk about the finale and make the video highlight reel, I want to tell a few stories about the planning, building, testing, and deploying of the stack. I wish I could tell you about all of the little experiences I had while doing so, but that would make an already long post even longer, so I’ll try to tell the most relevant pieces.

Stack Design

The stack design all began on the night before a fake stack sometime second term. We were out getting some delicious late night LA food after having finished our fake, and on the way there we confirmed that the three of us were working together. I proposed that our stack theme should be an original content time travel stack, and I think we all pretty much agreed at that point, since nobody had a strong opinion on something else they wanted. I had actually discussed how cool it would be to have a time travel-based stack with Matt a few years beforehand, so I was glad that the idea was getting implemented.

Then, we discussed how we wanted our stack to be flavored. Time travel could imply visiting historical events, or it could be a science fiction stack like ours. We chose the latter because we felt it would be more compelling to our target audience, as well as because it’d be kind of annoying to have to research historical events in addition to coming up with a good plot. Once we decided on a more sci-fi flavor, one of us (probably Matt) came up with the idea that it should be set at Caltech in the future. It seems like it might be a cheap cop-out, but I think it served to help the immersion without losing much.

Our remaining design challenges fell into two categories: plot and stack elements, the former being somewhat uncharted territory for us and people we knew. We spent months making regular trips to my room to have a “nice refreshing soda” (after our on-campus convenience store runs), where we sat in front of a Google doc that went from being a bullet-pointed list of things we needed to do to just a disorganized mind dump of stuff. Somehow this never really became a problem; I guess ctrl+f is a powerful thing.

I don’t remember much about how the plot developed. I think it sort of organically grew as the three of us contributed ideas. Matt is a pretty gifted story-maker, so his contribution was definitely quite valuable. Much of our time was spent debating details of our story and whether they were internally consistent.

For the stack elements, we had already developed some ideas for our bigger mainstays while we were underclassmen (definitely we came into the design process of the stack already having the preliminary ideas for what later became the mirror maze and the Space Alert puzzle). For the rest, we wanted to balance puzzles with activities (and, where possible, combine the two), as well as including at least one brute force element just for tradition’s sake. That’s how the minor puzzles came about: we just ran with some of our one-off ideas to balance out the stack and fill out the day. We did actually wind up having to cut one of the puzzles that we developed, which would have involved something to do with pinballs rolling around in multi-layered mazes that you controlled by tilting the entire structure.

The horrible mess of cables that threatened to take over my room entirely during the build process.

The horrible mess of cables that threatened to take over my room entirely during the build process.

When we actually got around to writing the detailed parts of our stack, including timings, we had to follow the advice given to everyone, which is that frosh are kind of dumb. A more charitable way to put that might be that it is difficult to gauge the difficulty of puzzles, even with play-testing by alums, when they’re developed in secret. The stack that I went on my frosh year created a slight workaround for this problem (I don’t know if they got it from anywhere). They made their puzzles a little bit on the hard side and included several envelopes with each puzzle with notes that said “open if still working at [time],” each of which offered successively more explicit hints, the last of which offered the answer to the puzzle. The reason they were made to be harder is that having a stack go too fast is pretty poor as well, as they need to be stalled with other puzzles (sometimes “best-of” puzzles from other stacks that are resettable) to fill out their day. We used this idea, albeit digitally, and it seemed to work out pretty well: our stack was actually almost exactly on time for at least half of the day.

Build and Test

A large part of building our stack was making sure that other people would be able to actually solve any of the puzzles, even if we did tweak the difficulty up. After all, much of engineering is about coming up with an idea and then iterating. Our progression was mostly to try it ourselves, then test it with each other, as much as possible, and finally test it with a group of alums. Sometimes a lot of changes happened during testing: the mirror maze got a few tweaks to difficulty and correctness with alum play-testing (I had a bug where holding down a button would cause the input to freeze for a while as the buffer cleared, so I put out instructions not to hold down buttons), the Skype puzzle developed from Matt’s original form to its final form over the course of a run-through or two with Jeff and me and later some other seniors, and the wire puzzle was completely redesigned when alum play-testing showed that its original form was kind of crap. It’s interesting to think back to this process, because it almost feels like we were doing UX design (certainly not something I’m good at), as we were testing how people would interface with our puzzles, and what was confusing or unsatisfying about the experience.

I felt like lord of the monitors when I still had the mirror maze controlling computer in my room.

I felt like lord of the monitors when I still had the mirror maze controlling computer in my room.

Of course, sometimes testing it had to sort of wait until the last moment. The only people around on campus who can test your puzzles are other seniors, and they’re often busy with their own stacks. The alums are very useful for this, but they only show up for the week before. That’s why much of the week before our stack was spent testing (thankfully we had the puzzles built in time). I would definitely advise any seniors reading this to build their stacks in time for alums to be able to run through it at least once. In addition to lack of QA manpower, many of our stack components were built in our rooms and couldn’t be moved on-site until the night before (since we didn’t have access to the spaces until then). Thus, we were forced to do some creative limited testing in our rooms. At least we were seniors, so we had the bigger rooms!


Ditch Day stacks are almost entirely self-funded, and ours was not cheap. Looking at our budget, it looks like we spent about $1900 total on the stack. The biggest expenditures were the $600-800 on the mirror maze (we spent $370 on mylar and about $185 for arcade buttons and controllers, though some of both were also used on the Space Alert Puzzle) and the ~$400 we spent on our shirts from CustomInk (for a total of 18 shirts: 12 for the stackers, 3 for us, and 3 for alums who helped a lot). As I’ve mentioned before, the tablet was only $55, which was awesome.

Some entries in our budget include “Ilya likes scotch” (Scotch Tape), “My(b|l)ar Part 2” (our second purchase of mylar — I think this was a reference to the Electric Six song “Gay bar Part Two” somehow), and “2800 feet of 32 gauge mag wire” (that one’s exactly what it sounds like). While dealing with the mylar, we often called it the “mylarium invectus domine”, mostly because we were sleep deprived and thought it sounded funny. The fact that the final code to the mirror maze was “MID715” was a callback to this that only we understood.

Fortunately for us, we managed to get a little bit of help with the money side of things. First of all, Blacker Hovse subsidized some of the cost of Ditch Day stacks, depending on how many spots were on the stack. The amount of the subsidy that my stack received was about $400. Furthermore, at the end of the year, the seniors hold a “garage sale”, in which they try to pawn their (sometimes useless) Ditch Day leftovers on the underclassmen. My stack managed to sell off about $420 worth of stuff this way. Thus, at the end of the day, we wound up spending about $1500 on the stack, which was “only” about $500 per person building the stack.

Overall, it is very much the case that more money does not make for a better stack and vice versa. We spent a lot of money because we were ambitious about the scale of our construction and at least partially because we were kind of lazy about shirts (which we’d still probably have to spend ~$150-200 on if we screened our own). However, other stacks in Blacker barely spent any money at all and received positive reviews. It really depends on your vision for the stack and what kind of flavor you want it to have. I’m grateful that my fellow stackers and I were willing and able to spend so much money!

Stories from the Day of

The day of Ditch Day started off pretty poorly for me, despite an awesome prior week. As I discussed before in part 3, a dumb issue with the Javascript for the app caused me to pull my first true all-nighter at Caltech, when earlier in the week we were speculating that we could actually get quite a bit of sleep that night (and if I remember correctly, my fellow stackers did get four hours or so). In fact, while I had gotten to bang on people’s doors to wake them up for every fake ditch day for which I was a senior, I had to miss doing so on the real day of for this reason.

Fortunately, I managed to get the issue solved before the seniors officially began Ditch Day by leaving for their undisclosed off-campus location (our off-campus alley, Munth), as being a senior on-campus during Ditch Day is fairly perilous. At Munth, I was running on adrenaline (and maybe a little caffeine) for the first while and helicoptering on the inputs that the people on our stack were giving us, as well as updates from alums who were watching our stack. However, after a little bit of time, I started crashing and wanted to take a nap. This was not very much in the cards for me, though, since I was apparently the only person on my stack who actually had alums’ phone numbers 😦

Our stack was quite perfectly timed in the morning. If I remember correctly, they were solving and arriving at puzzles within minutes of our schedule. This was, of course, helped a lot by our ‘clue envelopes’ and the fact that the people on the stack diligently used them when needed (which I don’t think was that often). At lunch, we were quite optimistic about our stack actually working out. There was one exception, which was the fact that our stack thought the mirror maze was broken for some reason when it wasn’t. I think it had to do with their accidentally muting one of the speakers. After lunch, Jeff and I cloak-and-daggered on-campus in the hopes that we could fix it so that our stack could do it at the end of the day (we found nothing broken, by the way). On the way back from that, we almost got duct taped to a tree by some underclassmen, but Jeff’s and my sprinting in flip-flops skills and the underclassmen’s apathy skills won the day.

The afternoon was a completely different story. It started off pretty uneventful, but we were soon getting reports that our stack was skipping elements (maybe the tying up of Kurt, maybe the wire puzzle sabotage, maybe something else?). I tried sending some messages over the tablet app to not skip things but it didn’t seem to be reaching them. More reports seemed to come in to confirm this news. A combination of confusion and sleep deprivation resulted in my getting very angry and frustrated, as I was worried that they were ignoring the plot, which was a pretty major component of the stack. I worried that this meant they would have hated the experience because of that. Other alums and seniors were trying to calm me down while I tried to take some deep breaths and see where the frosh wound up. It was overall a very stressful hour or so — it isn’t a fun feeling worrying that months of effort had gotten wasted.

In the end, it turned out that the frosh had just decided to split up to do the sabotage portion of the stack and completed it quite a bit sooner than expected, which was the cause of our faulty intelligence. Thus, it wasn’t the case that they missed fairly significant chunks of the plot. I calmed down quite a bit after hearing the corrected news, although apparently the news that I was very unhappy filtered through to the frosh when they decided to prank our rooms after getting done, so they skipped mine. I feel sort of bad for that.

When Ditch Day was over, we got to see the people who went on our stack and talk to them. That is when I found out that they had mostly positive things to say about the stack, which made me quite happy. I even had a junior tell me that it was the best stack he had been on. Thankfully, I got to end the day feeling that my stackmates and I had done a very good job, and we had a few days before our required clean-up to run our biggest puzzles for more people in the house!

One thought on “Behind the Scenes: Stack Design, Build and Test Process, Cold Hard Cash and the Day of

  1. Pingback: Ditch Day (Table of Contents) | Doing Awesome

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