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george hart
post Dec 18 2009, 05:37 PM
Post #1


Hart basically constructs mathematical shapes using playing cards. Thought this was cool.

It is one foot in diameter. Each card has four slits in it and they "simply" slide into their neighbors. No tape or glue is required, but the slits must be cut accurately for it to work well.

To assemble the cards, the tricky step is joining three together in a 3-fold lock, as shown above. Notice the little equilateral triangle in the center. Each point is on top of the next, around in a cycle. This is what holds everything from falling apart. I don't know how to tell you how to do this, but if you fool around and use the picture as a guide, you'll figure it out, I'm sure. A little bending is required during the assembly, but then each card becomes planar when done. Once you have mastered this lock joint, just join 20 of these 3-fold groups together as an icosahedron. You will form nice 5-fold stars with the slits at the other end of the card. The top image on this page is centered on one of the 5-fold stars.

This is an 8-inch diameter construction in which the 30 cards have more overlap, so it is trickier to make. All the joints are 3-fold locks, so it holds together very tightly. You can throw this around a room and it will not come apart.

full page

Seeing as how I have nothing else better to do, I might attempt this one day.

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