<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.

#!/bin/bash
declare {{a..h},{j..t}}="$((i++))" letters=({{a..h},{j..t}}); while read -r; do echo "${letters[18-${REPLY:0:1}]}$((20-${REPLY:1}))"; done