Rip 4chan. For all the bad it did, 4chan also made at least one real contribution to science [1], specifically to the study of superpermutations (aka the Haruhi problem), which was cited by genuine academics. We should try to remember it by that.
Given a set of characters, find the shortest string with all permutations of that set. With 2 characters a,b the answer would be "aba", length 3 (not 2! like you suggested).
[1] https://www.theverge.com/2018/10/24/18019464/4chan-anon-anim...