There was the panda bear in the sea of snowmen, or the lone cat amid all the owls. Then there was the hidden cigar in the brick wall. And, earlier this month, there was the phone hidden on the patterned rug. Every few weeks, it seems, some new “optical illusion” pops up on Facebook and is soon inescapable — that phrase is in quotes, by the way, because even though we seem to have agreed collectively as an internet to call these things optical illusions, many of them are really something more like puzzles, as Select All has noted.
Once you know where to look, in other words, it’s hard to imagine how you ever could’ve missed it. In a way, then, these silly little puzzles are an unlikely everyday example of the curse of knowledge, the idea that once you know something about something, it’s hard to see that thing in a fresh way, the way a novice would see it.