<b_jonas> slashlearn euclid//Euclid is a short geeky game in which the goal is to do Euclidean compass and straightedge constructions in as few steps as possible. It runs in the browser, found at "http://www.euclidthegame.com/". It was popular among #esoteric regulars in 2016-07.

tr -dc "AB,.<>+-"</dev/urandom|fold -w"${1-50}"|sed -n ":a;s/A\([^B]*\)B/[\1]/;ta;/[AB]/b;p;q"