Towards better understanding the behaviours of rattlebacks

Rattlebacks are rigid bodies which, when rolled on a table, exhibit a
unintuitive spin bias, due to small asymmetries either of the body
shape or of the mass distribution.  The nonholonomic model consists of
a convex body, quite a bit longer than it is wide, rolling without
slipping on a plane. It may be possible to understanding better the
motion of rattlebacks, by viewing the system as a (singular)
perturbation from a nonregular nonholonomic system. I will sketch some
preliminary work along these lines.