  Which convex 3D polyhedra can be obtained by gluing several regular hexagons
edge-to-edge? It turns out that there are only 15 possible types of shapes, 5
of which are doubly-covered 2D polygons. We give examples for most of them,
including all simplicial and all flat shapes, and give a characterization for
the latter ones. It is open whether the remaining can be realized.
