On Saturday, June 7, 2003, at 03:01 AM, Charles Martin wrote: > I am told that the wheels were weighted that plus momentum probably > did the trick. If the second, third and forth wheel had weights at the top gravity would help them roll up the ramp after they were pushed off the balanced position. This advantage would only hold true for half a rotation since gravity would act against the forward movement after that and only the first wheel turns more than half a rotation. Gerhard Kuhn suspice at hay.net