An attempt to sound both intellectual and as though you already knew something you most certainly did not. Usually this is in regards to something which had nothing to do with the current situation.
This is usually accompanied by a finger pointed towards the sky, as if to emphasize the ah-ha! factor.
a joke referring to the scalene triangle. originated by tumblr user coolscar, in a number of homestuck related posts. is well-known due to the confusion it causes.