He's real

[kresty]

Hmm, you need better behaved droids!

My thinking for the ball was that the inner drive car would have a single gizmo that could shove out a port in the ball.  Then I'd draw lines on the inside of the ball so that the car could detect the position of the outer ball, and therefore get to a position where a single opening port was aligned with the gizmo.  Of course that still leaves the challenge of figuring out how to make a port open and still have the inside smooth enough to drive on!