This three dimensional paper dragon is one of the weirdest things I’ve seen in a while. If you look at him (I can’t help but personify the little critter) and move around, his entire head appears to follow you. He’ll rotate it left and right or crane it up and down to hold you within his unblinking gaze. The effect is bizarre; I put him up on a shelf at work today and he’s stirred up quite a bit of curiousity.
The illusion works because the dragon’s head is actually concave, although it’s folded and drawn to appear convex like a real face (i.e. the snout appears to jut forward but actually recedes into the head). With one eye closed, the brain misinterprets the visual cues it’s receiving and constructs an animated 3-D object. There are two ways you can experience the illusion for yourself:
The hard way: It’s not actually that hard to print the dragon out from the provided .pdf file and fold it properly. The instructions look a little daunting but are actually quite simple. I’ve found that the best way to look at him is to place him on a shelf with his body rotated slightly to the right. Stand a few of feet away, close one eye, and move around. He’ll appear to follow you.
It’s also possible to make this work by holding the dragon in your hand and rotating it. This is a bit trickier, as the brain’s interpretation has a tendency to flip back and forth between the illusion and reality (like looking at a Necker cube). By focusing on the inner corner of the snout I’ve been able to make the desired interpretation click into place.
The easy way: Just watch the video (first link on the page). Since the camera doesn’t film with stereoscopic vision you don’t even have to close an eye (you lazy bum, you).
The dragon was designed by sceptic and illusion designer Jerry Andrus for an event held in honor of Martin Gardner in 1998. Additional examples of his work can be found here, where he also sums up how he approaches his work:
“I can fool you because you’re a human,” says Andrus, “You have a wonderful human mind that works no different from my human mind. Usually when we’re fooled, the mind hasn’t made a mistake. It’s come to the wrong conclusion for the right reason.”