solution: toroidal perpetual motion machine

[John Denker <jsd@MONMOUTH.COM>]

1) The physics of the meniscus is the physics of surface tension.

2) Surface tension is a force per unit length.

3) A force per unit length corresponds to an energy per unit area.

4) The area of any small patch of rubber shrinks as it rolls from the
outside to the inside, and grows as it rolls from the inside to the outside.

That's the essential physics that's been missing from the discussion so
far.  For more discussion, see next message.