(VRML Model)

After some thought, I realized it isn't necessary that the outer girdle of the Concentric Five-fold Prisms be arranged so a sequence of three connected side tendons connect adjacent struts to one another as in most non-girdled prisms. Here the girdle is connected to the inner prism so that a sequence of three connected side tendons goes from one end to the other end of the same strut of the inner prism. For now I think I'll leave this structure completely conceptual, but if you're interested in building it, the data is below. If you do build it, send me a photo and I'll put it here. This design was completed March 2, 2004.

This tensegrity reminds me of nothing so much as the witchs' cauldron in William Shakespeare's Macbeth:

1. Witch.   Thrice the brinded cat hath mew'd. 2. Witch.   Thrice, and once the hedge-pig whin'd. 3. Witch.   Harpier cries, "'Tis time, 'tis time." 1. Witch.   Round about the cauldron go; In the poison'd entrails throw; Toad, that under cold stone Days and nights has thirty-one Swelt'red venom sleeping got, Boil thou first i' th' charmed pot. All.   Double, double, toil and trouble; Fire burn, and cauldron bubble. ...   from Macbeth, Act IV Scene I

I received the first rendition from the audience from Eric Phillips, an undergraduate at the School of the Art Institute of Chicago, on March 22, 2004: Eric states: I used components left over from another project, but my sculpture class actually liked this one better. This was my first attempt at a tensional integrity structure (it probably shows) and I have to admit, once I got the hang of it wasn't as difficult as I thought it would be. I used twisted nylon twine, so it took a while to get the knotting down. I didn't have screw eyes, so I used bent hooks, but it worked. I left excess twine on for effect, and I let it lean heavily to one side. I thought it more interesting that way. I imagine it could use more tension. I usually decrease all the tendon lengths 2% relative to what they will be when they are prestressed. The tighter tendons I decrease more and the looser tendons less, but I make sure it averages out to 2% and I do all right, with fishing line anyway. I never have things lean like that. But wow, I never expected to get anything so quickly!