<oerjan> addquote <ais523> b_jonas: hmm, it\'s fairly surprising that you can make a coherent esolang whose primary feature is that it wasn\'t written by Donald Knuth

#!/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