1. icon for 2013: Planetary Survey
  2. icon for Puzzle Hunts
  3. icon for Projects
  4. icon for TCHOW

2013: Planetary Survey

This is the midwinter 2013-2014 puzzle hunt I designed for my younger brother. The design process got somewhat blindsided by some job interviews (leave things for the last minute and the last minute tends to move around on you), but the result was still reasonably playable.

Framing story parts will appear in this format.

This hunt is about a group of space explorers setting out to discover the secrets of a new planet.

The survey crew sat in their common room, looking out through the (simulated) viewport.

“Okay folks,” began Rachel, “I’ve just gotten the final mission description for this exploration. You want to hear it now or on the way down?”

Karl gave a shrug, “as long as we don’t need anything outside the standard load-out, I’m okay with saving it for the glide down.”

Samantha looked up from her mapping display, “same here. In fact, I still need to spec out our landing site.”

Rachel looked to the fourth team member. “Toby?”

Toby started, “sorry boss; this game has got me really entranced. Yeah, let’s leave the mission brief for the glide down.”

Rachel sighed to herself. It wasn’t that they were a bad team, exactly. Just not the most disciplined. Best to go with the flow and try to help out.

Who should Rachel help first, Toby (game) or Samantha (navigation)?

Mike chose to direct Rachel to help Samantha first.

As Rachel approached, Samantha was examining sensor readings from the planet.

“Hey Rachel,” she said, “I think I’ve figured out where we are most likely to find structures. Can you give me a hand with the navigation controller?”

“Sure. But you’re going to have to remind me how these things work.”

“It’s simple,” said Samantha, “basically you just plug together compute blocks and then tap your X and Y signals. I’ve got it set up for (4,2) right now.”

“So, what coordinates are we actually landing at?” asked Rachel.

“Anything within two cells of (43, 73)  should work -- so X should be between 41 and 45, and Y should be between 71 and 75.” replied Samantha.

And so the two put their heads together to come up with a result.

Can you figure out what they came up with?

Mike looks at the navigation board

(also: head-on image, pieces)

Each node's output can be routed to some other node's input. The "X" and "Y" taps can connect anywhere in the network.

To solve, Mike eventually wrote a matlab program to solve for potential X values, and then worked things out for Y by hand. After pinning together the solution on the navigation board and checking it, the story continued.

Rachel walked to Toby’s workstation, looking over his shoulder.

“So,” she asked, “what’s the point?”

“Well,” he said, “I think it’s pretty self-explanatory, at least on the surface.”

“But there’s more to it than that?” Asked Rachel.

“I... think so. I get the feeling there’s some deeper answer hidden in there, but I don’t know what. C’mon, have a try -- maybe we can find it together.”

Rachel pulled over another chair and sat down.

Here is the game Toby was playing. Can you find the hidden answer?

chesskoban screen shot

The game in question is Chesskoban, a combination of chess and sokoban that I cooked up for this hunt; it's a successful enough formula that I'm planning on creating a bigger and better version for release in the future.

Anyway, after playing for a little while, Mike managed to figure out the hidden answer and the story continued.

Could it be? Yeah, Rachel was pretty sure that was it.

“I’ve got it, Toby.” She said, and proceeded to explain her answer.

“Well,” said Toby, “I would never have gotten that. But I’m glad you did -- it would have nagged me forever.”

Soon, the course for their glider was plotted and the team was ready to leave. The team boarded the deployment glider through an airlock, and began plummeting to the planet’s surface.

“Okay people,” said Rachel. “I know we haven’t been out on one of these planetside missions in a few standard years, but I think we’re starting to get back into the rhythm of it. We’ll land and head for the site the scanners tagged. Toby, fill us in on the cultural details.”

“Well,” said Toby, “we don’t have any official records of this planet or contact with any inhabitants. Based on the local flora and fauna, it appears to have been terraformed in the standard old earth model, which tends to suggest it may have been either a landing site or a resting point for one of the lost seed ships from the first migration.”

”Of course,” added Samantha, ”it could be something far less exciting -- an abandoned shipping depot or unregistered vacation planet.”

“Oh the glorious life of a galactic survey corps employee,” grumbled Karl. “But at least the weather’s nice in this part of the planet. I hope we don’t have any reason to visit the ice caps.”

“Everyone, look!” Toby pointed excitedly out the front screen of the glider. “That structured metallic signature the scanners tagged is a city!”

“Or at least the ruins of one,” moderated Karl.

“Regardless,” added Rachel, “it gives us something to hike for. Toby, can you set us down on that road leading toward it?”


The road was in surprisingly good condition, and the team made rapid progress toward the city itself. Unfortunately, the city was protected by a surrounding wall and gate.

“Gate looks to be in good condition,” said Rachel to the others, “suggestions?”

“Perhaps the wall has collapsed elsewhere?” said Karl.

“Nowhere in view,” said Toby, “and the underbrush is pretty thick around the base. It’s not going to be a good hike.”

“Ow!” yelped Samantha. Then, looking down, “well, it wasn’t the most graceful way to do it, but I think I found our first artifact.”

Indeed, upon further inspection, what had looked like a hummock in the landscape covered in vines appeared to actually be a trash pile of some sort.

“Let’s look through and see what we can glean,” said Samantha.

Here’s what was in the pile. Do you have any ideas?

pile of lego blocks

(also: larger version, and different angles.)

Though somewhat simple, I think this was my favorite puzzle of the hunt.

Mike boggled for a bit and then realized what was going on and constructed an object.

“...and, that should be it,” said Rachel, snapping the last pieces into place. “I’m not sure what it is; though it seems like it would fit in that slot in the gate…” Rachel trailed off as she walked over to try it.

“It’s a key!” Toby stated the obvious as the gates swung open, and the artifact (again broken into pieces) fell from the gate into the pile from which they’d retrieved it.

In the main plaza of the city stood a giant building, opposite a spindly tower. The team agreed to split up to investigate the structures.

Would you like to follow Rachel and Toby to the tower, or Karl and Samantha to the building?

At the tower.

“I wonder what the significance of this tower was?” Mused Toby.

“It still seems sturdy,” replied Rachel, “perhaps if we climb to the top?”

Several flights of stairs later they came to the top of the tower -- a platform with large panels on one side and a pile of clear spheres on the other, and a scattering of tubes on the floor.

“If we could figure one how these tubes connected, perhaps we would understand what this tower was used for.” said Rachel.

Why don’t you give it a try?

Mike and Peg working on a puzzle

(download the pieces.)

This is just a straight-up challenging combinatorial puzzle. It took Mike and our mother a while, but they did eventually manage to solve enough of it to progress.

With the tubes connected, a receptacle near the spheres began to glow as energy coursed from the panels.

At the building.

Karl and Samantha found the building’s door to be locked, with no obvious slots for key objects or other ways of opening it. However, to the side of the door they found the crumpled figure of an automaton, with a smooth recess in its back and a glowing sphere nearby.

“I wonder...” mused Samantha, picking up the sphere and inserting into the slot.

It engaged with a click and the automaton surged to life.

“Sirs or Madams if you wish to enter the exchange, answer me a simple question.”

The automaton's game was a live-action puzzle -- he repeatedly asked "if this is N, then what is this?" while holding up hand signs. The solution wasn't the one you would expect if you are familiar with the standard formulation of this challenge.

Regardless, Mike figured it out relatively quickly.

“Thank you! Please enter!” Behind the automaton, the door slid open half way before grinding to a halt moments before the automaton collapsed. Apparently the door mechanism had drained the last of the energy from the automaton’s sphere, as it was no longer glowing.

Slipping through the half-open door, Samantha was struck by the incredible stillness. Rows and rows of automaton vendors, each slumped over or collapsed behind a cart, missing energy spheres.

“We’ve found some sort of mechanism to charge up a kind of... battery sphere? I guess.” Rachel reported their findings via radio to the others.

“Wonderful!” said Samantha. We need spheres down here. As many as you can manage.

“They’re kind of fragile,” said Rachel, “but I think we can work up some sort of transport system.”

Build a system to get the spheres down from the tower.

This challenge was the first of a series of construction challenges -- in this case, building a house-spanning marble ramp. This is something we used to do a fair amount as children with receipt paper. In this case, ribbon was all we had on hand, but it turned out to work really well.

Mike works on the critical transition section of the ramp photographing the result animated version

Despite the (somewhat) non-robust construction, this ramp managed to deliver three spheres in a row from the top of the tower to the abandoned building, which was the bar I set for reliability.

With the ramp smoothly operating, it was the work of half an hour to get charged spheres slotted into all the robots. As the last was connected, the automatons began powering up as one. At a booth near the front labeled “Tourist Information” one hawked a “Map Of The Colony.” The price was given in an odd assortment of colored and mix-colored gems.

“Can we afford this?” asked Karl.

“I’m afraid not,” responded Samantha, looking at the paltry collection of gems they had picked up while re-powering all the robots.

“Then why don’t you try trading up?” broke in the tourist shop robot “There are all sorts of bargains to be found. I’m sure enterprising folks such as yourselves can manage to find deals on the gems I require.”

Trade up your gems.

the bazaar

(download gems and rules. NOTE: though not listed, you should start with a grey and black gem.)

This was a trading puzzle, inspired by some ideas in Chris's thesis proposal. You get some gems and can apply some (two-way) rules to trade gems for other gems. Since trades consume and produce gems, they are basically linear logic rules, and the whole bazaar is an encoding of... well, Mike figured it out.

“Okay, the bazaar. That’s where we are.” Samantha read off the map.

“Central computing,” pointed Karl, “that might contain the data we need.”

“It’s on the other side of the island, though,” cautioned Samantha.

“I think we can improvise something, if we work together, and take it one step at a time” said Rachel.

Build a vehicle to cross the desert (four rubber band charges)

Build a glider to descend the canyons (one throw)

Create a bridge across the river

Mike made it through this suite of engineering challenges with his usual aplomb and willingness to attempt the easiest possible solutions.

Mike's band-powered lego car and paper airplane

The rubber-band powered LEGO vehicle needed to cross a large amount of the house with only four stops for rewinding, which required some gearing. The airplane portion of the challenge was pretty much just random (and required a fair number of tries).

k'nex bridge

The bridge needed to start on a book and span across a river (as represented by a sheet) without touching the sheet or the ground on the other side. For the record, I was entirely unaware that k'nex could bend this much. (Also, the large pile of random-seeming pieces at the right of the bridge is just that -- a large pile of random pieces used as a counterweight.)

“This can’t be the whole computing center,” said Rachel. “There just isn’t enough equipment.”

“What about this grid over here?” asked Toby. “Looks sort of like the uplink in our glider craft.”

“You’re right,” said Rachel, after considering for a moment. “If we could figure out where this was transmitting to, we could find the backing data stores and recover the planet’s history.”

Decode the transmission web.

Mike stands within the transmission web

(download tags; pairs appeared on the same string.)

The transmission web was a tangle of strings, each with two tags. Mike's an old hand at this stuff by now, so puzzled it out in no time.

“I knew it.” said Karl “I knew we were going to end up at the thrice-damnable poles from the moment I set eyes on this place.”

“If I’m reading the rest of this data correctly, there are six artifacts out there, scattered in the polar ice. Each is mutating its encryption key every 5 minutes. But if we can manage to scan them all within that time…” Rachel trailed off, excitement clear on her face.

“We’ve just got to find them all, and then figure out the right course.”


This led outside to a relatively simple run-around: find six locations in the forest marked with green flagging tape, then come up with a route that gets to each of them within five minutes. I don't have any pictures, but I can say that it was dark, cold, and raining. A strong inducement to finish this part quickly.

The data from the polar caps revealed that a colony ship had, indeed, landed on the planet; however, it had moved on and left no forwarding address.

(The End)