Puzzle Fonts by the Demaines (MIT father-son)

MIT Prof Erik Demaine (not at the Media Lab) and his artist dad Martin made these: Mathematical and Puzzle Fonts/Typefaces
You can read about it here:
Is This Some Kind of Code? You Can Solve the … - The New York Times
… an article which has great quotes like this:
“For the Demaines, these sorts of collaborations are cause for celebration: One more person successfully “corrupted” into the world of theoretical computer science.”

I especially like this one:

and for those creating an escape room (have any libraries done that?), this one looks promising: