Mine is built with recycled materials and easy to find, easy construction, so much so that I made in a few hours of work: this is the typical "weekend project"
Step 1: The cut
For information my triangles have a 70 mm side.
After cutting all blunt edges have sandpaper increasingly end, until I got these pieces as you can see in the figure. cute right?
Step 2: The holes
Each hole is exactly in the middle of the side wall and to maintain it correctly I made use of a drill press.
In order to maintain the correct position of each piece I helped upright vertically to the piece of scrap Board that, given its shape fit to keep the piece for a puncture that switched from side to side.
After they have been properly sanded, I switched to the next step: painting.
I colored and cherry-colored tubes that three triangles; the other three I left them to their natural colouring of Clearcoat.
After drying the paint I've got a rubber band and I slipped, helping me with a small probe consisting of a skewer set to end with a duct tape and locking it on the opposite side, tentatively with a stick sideways.
After completing all the steps in the holes, obviously alternating tubing to the triangle, I tied the two ends of elastic together keeping it pretty tight and I hid the knot in one of the tubes.