9 Things That Need To Happen Before Brooklyn Nine-Nine Ends
6. An Answer To The See-Saw Riddle
While many have undoubtedly forgotten about the Season 2 episode "Captain Peralta" and its see-saw riddle, it's a plot thread that was deliberately left dangling for comedic effect.
The riddle, set by Holt to his detectives is as follows:
"There are twelve men on an island, eleven weigh exactly the same amount, but one of them is slightly lighter or heavier, you must figure out which. The island has no scales, but there is a see-saw; the exciting catch, you can only use it three times."
After the squad fail to solve it, it emerges that the riddle was actually posed to Holt 20 years before by a commanding officer, and that he himself has been trying to solve it ever since.
While the relatively straightforward answer is readily available online, it was never solved in the show, and we have to assume that Holt is still grappling with it due to his meticulous nature.
Seeing Holt finally solve the riddle after a few more years would be an incredible pay-off to a very drawn-out joke.