In article , harry wrote:
The nearest thing I saw to perpetual motion was a little turbine in a
glass bulb that just rotated. It was suspended on a diamond resting
on a needle, ie very low friction. It was actuallypowered by light.
The turbine blades were shiny on one side and black on the other.
There was a vacuum in the glass bulb

Actually it relies on there being a very low gas pressure but not a
perfect vacuum, if you make the vacuum too good it stops working:
http://en.wikipedia.org/wiki/Crookes_radiometer