And you can see a little bit of double helix forming there.

You mix them together and they make a rigid double helix.

So when you shake the chain, it then folds up into any configuration that you've programmed in so in this case, a spiral, or in this case, two cubes next to each other.

When you look at DNA origami, you can see that what it really is, even though you think it's complicated, is a bunch of double helices that are parallel to each other, and they're held together by places where short strands go along one helix and then jump to another one.