Inverted Psi wheel

I have tried to rotate an inverted psi wheel.  I could rotate it.  It is done the same way as
normal psi wheel.

How to make inverted psi wheel:

Take a rectangular shaped aluminum foil. bend it  along the length so as to look like
a concave shape. To support the wheel, use a bulb. Since bulb is made of glass,
it has good finished/smooth surface and due to the spherical shape, it has surface of contact at a single point.