Mathy stuff I like

This is a personal collection of stuff I like or do, and that is at least somewhat related to math.

Solving math puzzles

There are plenty resources online, here are my favorites:

• Math puzzle collection: By Gurmeet Manku. Roughly 100 puzzles with solutions, the best of the best. (2nd place: Expii/solve.)

• Czech math puzzle collection: By Petr Kovář. No solutions but if the answer is numerical, you can have it checked.

• Weekly riddles: FiveThirtyEight.

• Youtube channel: 3blue1brown. (2nd place: Numberphile, 3rd place: polylog)

Proposing math problems

I'm quite involved in the Czech Math Olympiad. Here is a list of problems I proposed to international math competitions.

Puzzle hunts

Fairly popular pastime in the Czech Republic, as seen on Sifrovacky.cz. A short list of my favorite (czech) puzzles is here. For English speakers, a good starting point is PuzzledPint (takes place every month in a pub & for a couple hours instead of being held outdoors & overnight).

Ambigrams

See Wikipedia. I'm a complete amateur but I enjoy trying to make them. If you want to try that too, here is a handout to get you started.

On a related note: Is it crazy how saying sentences backwards creates backwards sentences saying how crazy it is?

Math jokes

A couple hopefully not-so-cringe math jokes, stolen from all over the internet (e.g. xkcd, SpikedMath, LanguageNerds):

..and a bonus joke-puzzle: What does the "B" in Benoit B. Mandelbrot stand for?