Optical Illusions

I have always loved those pictures which,  when you look closely at, you can see the initial image morph into something entirely different. There's a whole crop of really creepy ones where skulls suddenly appear. However, these examples are far more tame. The first one is on the outside wall of Magdalene College, Oxford and the other two are the same carving in the Wantage church but Mr GBT has turned one of them upside down.

Arilx