Excuse the MS paint, but:
Is it possible to isolate the yaw of the cylinder on this prism?
More clearly: Is there a mechanical way to have the rectangular prism rotate but the cylinder will not follow it?
For example, the entire system is facing north. The rectangular prism (robot) turns south, but the cylinder has not rotated at all. For any other non-rotation movement, the cylinder obviously still follows. So if it drives north, the cylinder will stay attached and come north with it.
edit: Please purely mechanical, with no gyro sensors etc