Ditch Day: Building “Sense”
Tumblr Dashboard reader: this one’s a doozie, and it’s full of videos. You’d like this post better if you read it on my site.
On my first Ditch Day, I rappelled down an aeronautics building, hunted live uranium with a Geiger counter, had a 300-bolt roman candle melee, and sent an Air Force officer to the emergency room.
So when senior year rolled around, I naturally wanted to top that.
Sometime in May each year, Caltech seniors ditch classes. That would be a typical college tradition, but things escalated.
While they were away, underclassmen pranked seniors’ deserted dorms. One found a car assembled in his room; another’s was turned into a swimming pool. So the seniors built elaborate “stacks” to keep underclassmen out: steel and concrete walls, booby traps, vicious puzzles, and the like.
Over the decades, Ditch Day has mutated. It’s now an opportunity for seniors to create an unforgettable adventure for the friends they’ll soon leave behind. It’s by far the most anticipated day of the year.
The date of Ditch Day is a highly-guarded secret (it’s always “tomorrow”), but it’s clearly imminent when alumni arrive in droves to help the harried seniors.
Oh, and we were harried. I’d been working on my stack, “Sense,” as my full-time job for weeks with my math-major accomplice, Mike Smith.
The day before, I papered campus with strange posters to stir up confusion and discussion. At dinner, each senior made a theatrical announcement about his stack; I got up and described an incredibly sketchy string of facts I found while looking into the posters: “You probably shouldn’t sign any waivers from these guys.”
The morning of Ditch Day, the underclassmen awoke to seniors pounding on their doors and screaming: “Wake up, frosh! It’s Ditch Day!” Our courtyard was full of prospective adventures, with the flyer at the top of this post advertising mine.
There were eight tabs on the bottom of that flyer. So what did those Techers find when they called that phone number?
Our plot was driven by “Mindvision Laboratories,” a suspiciously boring corporation whose experiments were recently shut down by the FDA. They were looking for volunteers to be… off the record. Things got fairly more sinister as the day progressed.
After an opening video and breakfast, our stackers went through a nine-hour series of experiments challenging their senses. I’d like to highlight a few of my favorites and show you how we made them.
Balance / Telepathy
Our stackers arrived on a secluded rooftop between two taller buildings and found huge steel pipes forming a mobile above their heads. The rods were anchored to the opposing rooftops and hung akilter just out of reach.
Each pipe had a mercury tilt switch mounted at its center. When all three were level, a relay opened, and an audio clue to their next location played over loudspeakers.
Of course, we didn’t give instructions, here or in any other experiment, so part of the puzzle was: what is the puzzle?
By carefully coordinating who grabbed the bars where, they balanced the mobile and got their next location. But it also made a great toy, even after Ditch Day was over. Here are some friends playing with it:
My original plan for building this was along the lines of “Andy finds some rope, ties some overhand knots.” I mentioned it to a rock-climbing alumnus, who gently pointed out that the system is about 2,000 lbs under load and Andy let me teach you about ropes please.
Taste
I gave my stackers a Flip and told them to record their day. This is the hour they spent failing to solve this puzzle, compressed to two minutes:
Each student got a box of four gels, and each gel had three of the primary flavors: salt, sugar, acid, spice, and bitterness. Every box had an exact twin, and pairings corresponded to letters on a grid. When anagrammed, the letters spelled out the next location.
What about the clues they were reading? We didn’t give any instructions, but we left Remedial Envelopes stamped with “open by” times so they wouldn’t get too far behind—they had a full day ahead!
The gels were simply agar and food coloring, flavored with salt, sugar, vinegar, jalapeño, and orange peel. They were meant to be vile, but I still think these guys were being wusses about it.
Hearing
This one took place in the dark, so there are no good photos, but I’ll narrate it from the students’ perspective:
They arrived in a conference room dimly lit by a desk lamp. A sign read simply: “Hearing.” Two dozen speakers were mounted on the walls, ceiling, and furniture. Each had a button taped to it.
After some confusion, someone pressed a button. Suddenly, the light went out, it was pitch black, and the Ride of the Valkyries started playing out of one speaker.
That song is played by enormous speakers at 7:00 AM every finals week, and it’s not allowed to be played any other time. Techers have a rather violent ingrained reaction to it.
They scrambled in the dark, randomly pressing buttons until someone hit the one on the Ride’s speaker. Silence—then all the speakers started loudly playing snippets of Bach fugues, at random offsets and rapidly shifting volumes.
One speaker also played the Ride. After a few seconds, they all shouted “MISSED!” The stackers pressed more buttons, but the room kept yelling “WRONG! Seven to go.”
Eventually they figured out the challenge: they needed to hit the button on the speaker playing the Ride before it moved after a few seconds, seven times in a row. That required a great deal of coordination in a pitch black, very loud room full of hazardous rolling chairs.
The whole thing was run by a script on a computer with five sound cards. Coordinating 24 independent audio channels was… exciting. The buttons were connected to a USB keycoder.
How’d I have the computer turn off the desk lamp? I carefully placed the power strip’s switch in front of the CD drive and made it eject.
I used almost 1,500 feet of double- and triple-conductor wire for this room, but it was all worth it for this very sweet note they left me:
Pain
This puzzle’s footage makes me giggle with disconcerting glee:
Some of the pairs of nails were connected to 15 volts. When the stackers colored in the live grid squares, they got a location:
There are so many more stories—including the one where I made them take unlabeled pills (miraculin!) in a dank maintenance room—but I’ll stop here to save some of those virtual trees I’m chopping down.
So that evening, awake for 41 hours, all I could think was: “I wanna do it again!” My kids are gonna have the coolest birthday parties.
Balance/Telepathy photo by Michelle Hasier.
Video and flyer photo by Ilya Nepomnyashchiy.
