The Business Card Menger Sponge Project

Menger's Sponge (depth 3)


The primary goal of the Business Card Menger Sponge Project is to build a depth 3 approximation to Menger's Sponge, as shown above, out of 66,048 business cards . This can be done by building 8000 business card cubes out of 6 cards each, linking them together and using the additional cards to panel the 18,048 exterior faces of the sponge.

I am looking for volunteers to help me build this. I have devised a decomposition of the sponge into simple units that almost anyone can learn to make, which can then be assembled into the whole. I will provide complete instructions and materials. Volunteers will need to commit about an hour and a half of time (more, if you like), and pay for postage. I am also planning a variety of sponge building activities in the Boston area, and possibly other locations, in the coming year.

The sponge, when finished, will measure slightly over 54 inches (140 cm) on each side and weigh about 150 pounds (70 kg). This leads us to some interesting structural considerations.

I intend to donate the finished model to a suitable museum.

How long will it take to build? I have completed a paneled level 2 sponge using 3456 cards, and it took me about 30 hours. So I imagine that I could finish a paneled level 3 sponge in about 600 hours. It would probably take most other folders somewhat longer -- I'm pretty fast. I could probably finish it by myself, but then I couldn't claim workman's compensation when I got repetitive motion syndrome. I would rather do it with a little help from my friends.

Anybody interested?


j9@world.std.com