  Experiment shows that dumbbells, placed inside a tilted hollow cylindrical
drum that rotates slowly around its axis, climb uphill by forming dynamically
stable pairs, seemingly against the pull of gravity. Analysis of this
experiment shows that the dynamics takes place in an underlying space which is
a curvilinear polyhedron inside a six dimensional manifold, carved out by
unilateral constraints that arise from the non-interpenetrability of the
dumbbells. The energetics over this polyhedron localizes the configuration
point within the close proximity of a corner of the polyhedron. This results
into a strong entrapment, which provides the configuration of the dumbbells
with its observed shape that leads to its functionality -- uphill locomotion.
The stability of the configuration is a consequence of the strong entrapment in
the corner of the polyhedron.
