| How can you expect to achieve the maintenance of a local orientation while spinning on a global axis? It's a bit like asking how can I walk a mile west and end up where I started? You can only do this under particular circumstances, and you give an example of one where you tip on the x-axis and spin on the global z axis. This works because the local x-axis remains at right angles to the global z-axis. After an arbitrary reorientation on the x-z plane it won't work. |