## Mathy Review of the 2019 MIT Mystery Hunt

Every year I review MIT mystery hunt from a mathematician’s point of view. I am way behind. The year is 2020, but I still didn’t post my review of 2019 hunt. Here we go.

Every year I review MIT mystery hunt from a mathematician’s point of view. I am way behind. The year is 2020, but I still didn’t post my review of 2019 hunt. Here we go.

Many puzzles in 2019 used two data sets. Here is the recipe for constructing such a puzzle. Pick two of your favorite topics: Star Trek and ice cream flavors. Remember that Deanna Troi loves chocolate sundae. Incorporate Deanna Troi into your puzzle to justify the use of two data sets.

On one hand, two data sets guarantee that the puzzle is new and fresh. On the other hand, often the connection between two topics was forced. Not to mention that puzzle solving dynamic is suboptimal. For example, you start working on a puzzle because you recognize Star Trek. But then you have to deal with ice cream which you hate. Nonetheless, you are already invested in the puzzle so you finish it, enjoying only one half of it.

Overall, it was a great hunt. But the reason I love the MIT mystery hunt
is because there are a lot of advanced sciency puzzles that can only
appear there. For example, there was a puzzle on Feynman diagrams, or on
characters of representations. This year only one puzzle, Deeply Confused, felt like *AHA, this is the MIT Mystery hunt*.

Before discussing mathy puzzles I have to mention that my team laughed at Uncommon Bonds.

I will group the puzzles into categories, where the categories are obvious.

Mathy puzzles.

- Bubbly—Combinatorial game theory.
- Rules of Order—Fractals mixed with movies.
- Cubic—A long list of cubic polynomials with integer coefficients.
- Twisty Passages—Famous number properties that remind my of my Number Gossip website.

Here are some logic puzzles, in a sense that Sudoku is a logic puzzle.

- Lantern festival—A cool mixture of Slitherlinks and Galaxies.
- Invisible Walls.
- Place Settings.
- Middle School of Mines—Minesweeper.
- Moral Ambiguity—Nonograms with a twist.
- Connect Four—Mastermind. There was a strong hint that the extraction step was also mastermind. My team spent some time trying to mastermind the ending, until we backsolved. The extraction step was not mastermind. The final grid in the puzzle had the word CODE written in red. It corresponded to letters CDEO found at that location. Given that the letters were not in alphabetical order, it gave the ordering, which didn’t exist in the puzzle. Anyway, you can see that I have a grudge against this puzzle. This could have been a great puzzle. But it wasn’t.
- Schematics—Tons of Nikoli puzzles of different types.

Now we have logic puzzles or another type, where you need to draw a grid. These are puzzles of the type: Who lives in the White House?

Now we have logic puzzles or yet another type, where you need to figure out which statements are true and which are false.

Now some cryptography.

- Tales From The Crypt.
- You’re Gonna Need a Bigger Gravy Boat.
- The Bill.
- Helvetica Is Only an Okay Font.
- A Good Walk Spoiled—Some decyphering and Vim.
- Have You Seen Me?
- Chain of Commands.
- Picture Book.

And some programming.

Miscellaneous.

- Hexed Adventure II: Hexed Again!—A text adventure game with a lot of logic.
- Loaded—Dice of different shapes.
- The Lives of Π—Large numbers.
- Battle of the Network Stars—A lot of actors in a grid.

## James:

Thanks Tanya – looking forward to exploring! In a few cases, you have linked to the solution not to the puzzle (Bubbly, Place Setting, Moral Ambiguity).

29 March 2020, 9:57 am## tanyakh:

Thank you, James. I fixed it.

29 March 2020, 1:02 pm## Gaute:

Thank you Tanya, for the set of lovely puzzles!

4 April 2020, 5:52 amI have a question or criticism on the Bubbly Puzzle, or maybe it is obvious/trivila/part of the puzzle, I have not really looked into it enough:

Given the setup of the rules (or the “real life” situation), it is not clear what happens to bubbles A, R, G, etc. if I pop bubble L in the first puzzle?

I assume bubbles A, R, G etc. remain intact if I pop bubble L.

## tanyakh:

Gaute, This is a mathematical puzzles. This means you can make any unrealistic assumptions for the beauty of it.

4 April 2020, 10:39 am