Cypherpunk Ben Laurie (owner of the remarkable Bunker data-center in the UK) has a cool hobby modeling "ideal knots" ("a knot whose form allows you to tie that particular knot with the least possible string. More formally, its the shape that mimimises L/r where L is the length of the centreline and r is the radius of the largest tube you can put around that centreline without self-intersection. Or you can think about r as being fixed, and simply minimise L, which is what I said in the first place.").
He's posted a really sweet video of one of these 3D-modelled knots rotating around and around. This is really hypnotic geometry.
(Thanks, Ben!)
