Can You Solve This Shadow Illusion?

When sunlight shines through a small hole, it casts a circular image on the wall regardless of the shape of the hole. The size of the hole also doesn t affect the size of the image. This counterintuitive demonstration shows that the hole is acting like a pinhole camera, producing an image of the sun on the wall. Therefore the size and shape of the hole have no effect on the size and shape of the image.