<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.

bitcoins are coins that have been drilled through with a bit, and can be strung together in long chains. This practice dates to ancient China, and the Chinese remain experts in bitcoin manufacturing. A chain can support up to 21 million coins before breaking.