I guess almost everybody who reads this blog also reads Boing Boing (Hi Mum!). But you might not have noticed the papercraft dragon they posted a week or so ago, or you might have thought “That’s kinda cool” and then moved on in your busy and exciting lives. If you skipped it, or missed it, or whatever, I suggest most strongly that you go take a look, print it out and play with it.

Here’s the deal: it’s a cut-out-and-fold-up paper model of a cute little dragon with big teeth. The trick is, the way it’s folded your depth perception gets confused and it looks like he’s watching you, his whole head is pointed at you, even when you move around. The illusion is extraordinarily strong; the whole head twists on the neck, pivots up and down too, to follow your every move. (There’s a video clip on the site, I didn’t figure it would look as cool as that but it’s actually pretty accurate.)

There are two tricks to making this work. The most important is lighting: if this goes wrong the whole illusion collapses. He’ll do his thing reliably if you keep him out of direct lighting (to avoid giveaway shadows). He also works fine for me with his cheek lit but the top of his nose in shadow (more weirdness: it looks as if he’s lit from the opposite side to where the lamp is actually sitting!) but direct light on the whole snout breaks it, at least for me.

The other trick is, to hamstring your depth perception, close one eye. It’s a bit like the Necker cube, which you can see “inwards” or “outwards” by an effort of will. Move your head around a bit, and imagine that he’s looking at you. Pretty soon he will be. (After playing with him for a half-hour or so, and moving him into the shade, I get the effect with both eyes open.)

So go there, now, and print that PDF out. Mine is just ordinary A4 lightweight paper, and he’s standing up fine, although I’ll probably do a colour version on heavier card if I ever get around to it. It’ll take you about seven minutes to cut him out and stick him together (I suggest printing two copies, one for reference, because the folding is a bit counterintuitive around the head region). You won’t regret it.

(He’s too cute to give you nightmares.)