<oerjan> learn A zygohistomorphic prepromorphism is used when you really need both semi-mutual recursion and history and to repeatedly apply a natural transformation as you get deeper into the functor.

#!/bin/sh
topic=$(echo "$1" | tr A-Z a-z)
[ -e "wisdom/$topic" ] || { echo "$1? ¯\(°_o)/¯"; exit 1; }
cat "wisdom/$topic"