  We address the unsolved problem of unfolding prismatoids in a new context,
viewing a "topless prismatoid" as a convex patch---a polyhedral subset of the
surface of a convex polyhedron homeomorphic to a disk. We show that several
natural strategies for unfolding a prismatoid can fail, but obtain a positive
result for "petal unfolding" topless prismatoids. We also show that the natural
extension to a convex patch consisting of a face of a polyhedron and all its
incident faces, does not always have a nonoverlapping petal unfolding. However,
we obtain a positive result by excluding the problematical patches. This then
leads a positive result for restricted prismatoids. Finally, we suggest suggest
studying the unfolding of convex patches in general, and offer some possible
lines of investigation.
