Double-Take-Causing Illusions of Warped Perspective

The eye is as good at identifying things as it is at misidentifying things, hence all these intriguing illusions of strange perspective. A small amount of playing around with the background and foreground of an image, or messing around with light and shadows can easily make one thing look like an impossibly different thing. It doesn't take a lot of skewed perspective to cause a double-take.