What's the longest possible forced repetition in Go?
Molasses ko: http://denisfeldmann.fr/bestiary3.htm#mol

"The semeai in figure 11 is probably the worst known case of repetition. Known as "molasses ko", ..."

Denis Feldmann's Go Bestiary is a compendium of various things (interresting semeai, life and death, edge cases, incredible problems, rules edge cases, weird sekis, etc).