Outreach

How to solve the 15-puzzle blindfolded (April 22, 2017)

A 1.8-hour course for local high school and middle school students (2 sections, 15 students each), taught through Stanford SPLASH.

Class Description: "By the end of this course, you will know how to solve the famous sliding puzzle blindfolded: take an unsolved 15-puzzle, memorize it, then solve it with your eyes closed. Along the way, we will learn about a mathematical concept called permutation. 15-puzzles will be supplied. There will be plenty of time allotted for practice."
Handouts: exercises, solutions, partial write-up.

(The idea is simple: "Down Right Up Left" does a "basic 3-cycle" around the empty piece. Memorize the cycle decomposition of the permutation of pieces. Decompose each cycle as a product of 3-cycles, each of which can be solved by conjugating a basic 3-cycle, plus possible a 2-cycle. Solve pairs of 2-cycles using two 3-cycles. This is also how people solve the Rubik's Cube blindfolded.)

The coset method for the Rubik's Cube (February 9, 2017)

Write-ups produced as mathematical advisor for an event at Johns Hopkins University to promote the book Cracking the Cube by Ian Scheffler, hosted by the Hopkins Undergraduate Society for Applied Mathematics (HUSAM).
Handouts: problems, solutions (incomplete).

A Commutative Diagram of the Heavens (March 15, 2014)

Invited talk Math Day at the Beach, an annual high school math competition at California State University, Long Beach. Full slides.

A talk about the planetary days for a mathematical audience. The material here is certainly well known. The presentation is original and is inspired by conversations with Brian Lawrence. Here's an amusing application of this material: if you know Chinese and (say) French, you can figure out the days of the week in Japanese. With a little more effort, you don't even need French.