Couldn't accomplish this in a comment to Rahul's #1, but here is a physical realization of my drawing with colored pencils. Compare: ![alt text][1] ![alt text][2] The pencils are in contact, but the lead inside could serve as lines in space without contacts. I don't know how to reconcile this with your quote from Whiteley... [1]: http://cs.smith.edu/~orourke/MathOverflow/weaving4.jpg [2]: http://cs.smith.edu/~orourke/MathOverflow/pencils4.jpg