## Wind plus geometric objects equals fun

I was bored then. Back when I was a young boy, I was flipping through my favourite math encyclopedia book, and there was a section on geometric objects.

There were pages illustrating the outlines of the simpler geometric objects such as the tetrahedron, the cube and the octahedron. This meant I could trace the outlines on paper, cut them out, fold accordingly, and I would have the geometric objects in my hand, in 3D. Totally awesome.

[The name card holder is there to give perspective on the actual size of the objects. No, I didn’t keep the old ones. Those are newly cut and folded.]

So I was happily cutting and folding papers, and the Singapore weather being it’s hot usual self, forced me to position an electric fan aimed at me so I could be cooled. The completed geometric objects, being their feather-light selves, started flying all over the place. A light bulb kringed.

“Can I direct the wind so the objects move in a particular direction?”

Alright, perhaps my young mind didn’t form such a profoundly complicated question. I think I just reacted. I took a few more books from the encyclopedia set and arranged them to form my fake wind tunnel.

[I didn’t actually used clips to hold the pages down back then. The books were pretty well read, so the pages were pliable, so they conformed well to the book being split apart.]

The idea was to create a “valley” for the geometric objects to fly through, powered by my industrious little electric fan. It’s very exciting to see the objects fly out at the end of the tunnel.

There were some points to take note. First, wind power. I couldn’t form too long a tunnel with the books, because the wind wasn’t strong enough. I found I could make better use of the wind if I covered the top with another book (I didn’t use the clips then, so the top was level). That gave me another book length of fun.

I also found the type of object to be significant. I mean, can you imagine a pyramid-shape flying along? The wind would just flow upwards on its sides. The cube did better. But it was the octahedron that was the winner.

Out of the shapes I made, I was able to create objects of up to 8 sides. I might have created a 12-sided one, but I can’t remember. The difficulty was in the sticking of edges. With more sides, it’s harder to ensure the edge flaps stick to the inside of the object. With the tetrahedron, I could “squeeze” the edges to make them stick better. If I did that with a dodecahedron, the object will crumple.

Anyway, it makes sense. The more sides the object has, the more spherical it becomes. And we know how spheres love rolling along.

So the best setup I had was to place the fan really close to the entrance of my wind tunnel (to minimise escape of wind energy), place a couple of books over the top (to minimise escape of wind energy, but not completely so I could see the action), dump a few cubes and octahedrons (because they were the better flyers/rollers), and watch the little coloured critters fly out at the end. Absolute entertainment.

So that’s what I amused myself when I was a child. What did you do?