Pareidolia is a type of apophenia, or seeing patterns in random data. In other words, seeing/hearing something that really isn't there. The most classic examples of this come from our cars. The front of many cars can be seen to resemble a human face. With the headlights forming the eyes and either the intake grills or the bottom of the chassis forming a mouth. Pareidolia can also be seen when recognizing a face or eyes in a tree. The face shown has eyes, a beard, and a bit of paint added to it, however the shape that reminds us of a face was there originally. However it turns out, faces on trees are pretty rare, but eyes are not. Knots on trees can look very similar to eyes and some trees are covered in them, almost resembling Argus, the eye covered monster of Greek Mythology. Pareidolia most likely came to us through evolution. It is safer for humans to recognize faces even when there are none in the case of our own survival. Humans are much more likely to survive if, for example, they recognize a tiger face quickly and get out. Pareidolia is a great example of something that we evolved to have for our own safety, but now is simply amusing.