Most of the time, luck has it that even if our pictures aren't good, they turn out in a way that at least makes sense. Our eyes may be closed or we may be making a weird face, but it's nothing a quick delete can't fix.
But every now and then, we may find ourselves staring at a photo that we can't bring ourselves to get rid of. Even if we knew exactly what we were looking at, we might find that it's hard not to see a mind-bending effect thanks to the lighting or the way things are arranged in the frame.
And while these accidental illusions can be compelling to keep, it's even more fun to put them online and weird everybody out as the people on this list have done.