<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.

After the London terrorist attacks of 2005, the Underground was completely evacuated. Without air resistance, the trains would go at blazingly fast speeds between the terminals. This is called a vacuum tube. Sadly, current technology doesn't let passengers travel that way.