(With more attention to scanning Carroll’s reflections than to reflecting physics’ conjections)
The polehode rolls on the herpolhode, slipless in the invariable plane.
And when it slips the herpolpode quips “That’s non-holonomic to me”
But asymmetric jax-es flip intermediate ax-es, and quimbling experts explain
That the spunracket rode in an unstable mode as any spacecaptain could see.
Source: Poinsot Construction via Alejandro-Jenkins on What-is-the-most-difficult-concept-to-grasp-in-physics (and this video)