like the ring chainsaw,
the inner mechanism of the sphere,
the spinning ring, need not be two.
but just one,
if held and spun by the 'pillars'
from its sides.
think about how the ring chainsaw
is spun around. it is sandwiched
between gears top and bottom.
however, even with the weighed portion,
the sphere may not move.
the entire ring may need to
move toward the direction,
protrude. it may not need to hit
the inner surface of the sphere,
but that may be required to
create any sort of momentum....