On 3/13/10 11:35 AM, john wrote:

Have none of these people ever played with
elastic-band powered airplanes?
You twist and twist the propellor and at
some point, the elastic band does a
little flip and there's a knot.

Try dipping in liquid nitrogen first, John.


It's a 3D universe. Rotations
want to balance with orthogonal rotations
and so generate them.

john