Cross-Pollination

The Hunt:

Over a thousand people came together to solve puzzles at the 2014 MIT Mystery Hunt last weekend. Unlike "normal" puzzles, the ones solved at this event usually have no instructions. The fun is in figuring out what to do. You can check out all the puzzles on the hunt website.

The Puzzle:

I was a member of the writing team this year. One of the puzzles I co-authored was called Cross-Pollination. The rest of this post discusses how the puzzle was created, so if you'd like to give it a shot, you can check out the puzzle first.

The puzzle consists of four videos showing how to fold different origami flowers, and two crosswords. The solver must solve both crosswords, then fold them into the first two flowers. The flowers reveal answer phrases that point to two other crosswords, published in newspapers that week. Folding these into the remaining designs reveals the answer to the puzzle. Here is a detailed solution.

The Idea:

The genesis of this puzzle came from Erin Rhode, the writing team director. She loves the New York Times crossword and wanted to incorporate it into the hunt somehow. The obvious idea was to use the crossword that would run on the Friday the Hunt began. Since crossword editors often change clues, using only the crossword grid in our puzzle would be safest. We contacted Will Shortz and he graciously agreed to run a themeless puzzle on that Friday.

I wondered if we could publish crosswords in all the major newspapers that day, but it seemed too risky because if even one of those crosswords failed to be printed, the entire puzzle would fall apart. We concluded that using two newspapers - the MIT Tech and the New York Times - was more realistic.

Several people spent the next few weeks brainstorming ideas for how to use these grids. Eventually, we came up with origami as a theme. Origami paper and crossword grids are both typically square, so folding grids into different origami shapes is natural. We would provide some number of starting crosswords along with origami instructions. The solver would complete the crosswords, then fold them into different shapes to reveal a message that would lead them to the two newspaper crosswords, which themselves would have to be folded.

The Flowers:

My co-author, Quinn Mahoney, searched for different types of origami shapes that, when folded with a crossword grid, would display a small set of letters prominently. These letters would constitute answer phrases. Flowers are a common type of origami, and Quinn was able to find several different flowers that fit this criterion after experimenting with dozens of designs.

Photo of Quinn's origami Photo by Quinn Mahoney

The Bees:

The first two crosswords had to incorporate an interesting theme so that they weren't just typical crosswords. I wanted this theme to relate to the origami flowers in some way. Since each crossword is folded into a flower, I thought of bees traveling between them, as in cross-pollination. A natural theme mechanism resulted: the two grids contain BEE rebus squares in the same locations, and when one entry hits a BEE square, it continues in the other grid at the same location - these entries resemble bees traveling between the two flowers. This is the type of difficult twist required to keep Mystery Hunt solvers on their toes. The natural instinct is to start with one grid or the other, but here the only way to solve them is simultaneously.

These grids were challenging to construct for the same reason. I had to place BEE squares in both grids at the same time, then determine the entries that would pass through them. Each entry contributes letters to both grids. Also, I prefer to avoid duplicating rebus words (for example, BEER should only appear once in both puzzles) and BEE is a relatively uncommon string. Finding enough theme entries, particularly short ones, was difficult.

The Tech:

Folding the first grid into the poinsettia reveals WEDS TECH around the flower's petals. I arranged with the Tech to publish a special crossword on the Wednesday before the Hunt. This crossword needed to be fun as a standalone puzzle and relate to MIT in some way. Since I wanted to use MYSTERY HUNT as a theme answer, I began thinking of other IAP traditions. When I came up with INTEGRATION BEE, I knew I had to use it because it continued the BEE theme. CHARM SCHOOL, a class that teaches MIT students esoteric skills such as how to carry a conversation with another person, also appears. Many of the clues relate to MIT or science and engineering topics. The answer word NUMBER also had to be hidden in the Tech grid, which is revealed when the grid is folded into a sunflower.

Interestingly, the Random Hall team that won the hunt noticed the crossword beforehand and were suspicious, but to my knowledge they didn't find the hidden answer prematurely.

The Times:

Folding the second grid into the rose reveals FRI NYT. Quinn and I both loved the rose design because the answer letters are hidden until the very last step when the corners are folded in the center of the flower, revealing the answer letters plainly.

The Times grid would contain the answer word THEORY, which would be revealed after folding the grid into the cherry blossom. I was worried about how constraining these letters would be. My goal was to produce a high quality themeless without any sacrifices despite the constraints. The 6 letters and 2 black squares had to be positioned in 8 particular squares, but luckily with rotational freedom.

NYT grid with 8 constraints

I began by creating a 4-stack configuration in two corners, each of which contained two of the six letters. I figured that if these stacks were filled well, there would only be one letter in each of the other two corners and completing the grid wouldn't be impossible. Using H and T in the top corner, and O and R in the bottom, seemed like the most promising configuration.

NYT grid with 8 constraints and black squares

The corners weren't as lively as they could have been with no constraints, but overall the result was good. Amazingly, HONEY BEE found its way into the top left corner, completing the thematic link for all the crosswords.

NYT final grid

On a related note, I wrote a critique of the crossword at xwordinfo.

The Erratum:

We were anxious the week of the Hunt because we needed to make sure the two newspaper crosswords were actually published. Fortunately, we confirmed the Tech several days before the Hunt happened. It also looked like the Times had come through as well, because every crossword is released online early and we were able to check the online version was correct the night before. Relief!

That morning, however, we learned that some miscommunication at the Times had resulted in a different crossword being published in the physical paper, even though the online puzzle was correct. It might be the first time such a mistake has happened. Much confusion resulted on Twitter and the blogs, some of which wondered if Mystery Hunt was involved somehow. We issued an erratum to the teams informing them that "Wonderlandians had developed an irrational distate for print media" and instructed them to check online if they needed to consult any recent magazines or newspapers. Fortunately, we didn't give away where the Times crossword was used in the Hunt, and it looks like no teams were able to short circuit the entire first half of the puzzle. All in all, the mistake simply made for a better story.

Solution