A simple real life illusion: the transparent knife!

Take a look at this photo — it almost looks like a “transparent” or “camouflaged” knife! I snapped it years ago at a magician’s party. The trick here is all about specular reflections. It’s a simple illusion, but surprisingly effective. When you place a knife blade between the tines of a fork, it reflects nearby objects, making the blade seem almost invisible.

Image taken from my book “Optical Illusions: An Eye-Popping Extravaganza of Visual Tricks“, available from Amazon.

Below is another interesting variant: a transparent knife on a café wall illusion, two illusions in one!