Faces, faces

American Express has this neat commercial where they've created happy and sad faces out of everyday objects:



It's easy to do, of course, because human brains are more or less programmed to identify faces; almost any upside-down triangle arrangement has a chance to trigger this sort of recognition. Amex did a clever job of choosing unexpected objects to represent the faces, but they were able to make them quite clear.

Sometimes you come across a natural arrangement that isn't quite so perfect, yet still triggers recognition - an even stronger indication of just how prone we are to finding faces. For example, this goofy, but happy, tree: