Pareidolia is the word used to define both visual and audible phenomena where the human mind perceives patterns in random objects and translates them as something meaningful. Audible phenomena is best described as hearing words or messages when music or speech is played backwards, such as back masking or in some cases phenomena such as electronic voice phenomena [EVP].
Visual Pareidolia which is much more common is seeing faces and figures such as ghosts, religous apparitions, or structures on Mars or the moon where none should be. Some will naturally view these images as pure coincidence, some as meaningful coincidences.
Pareidolia frequently mirrors some aspect of a persons belief system. A Scandanavian study  concluded that religous people or those who believe strongly in the paranormal are more likely to see faces and patterns in inanimate objects, clouds, and so forth.
Renaissance artist Leonardo da Vinci was well aware of the phenomena and wrote of it
"If you look at any walls spotted with various stains or with a mixture of different kinds of stones, if you are about to invent some scene you will be able to see in it a resemblance to various different landscapes adorned with mountains, rivers, rocks, trees, plains, wide valleys, and various groups of hills..."  .
'The human mind delights in finding pattern so much so that we often mistake coincidence for profound meaning. No other habit of thought lies so deeply within the soul of a small creature trying to make sense of a complex world not constructed for it.' Stephen J. Gould 
1. Paranormal and Religious Believers Are More Prone to Illusory Face Perception than Skeptics and Non-believers
2. Discovering DaVinci
3. The Flamingo's Smile: Reflections in Natural History