  Can one build an arbitrary polytope from any polytope inside by iteratively
stacking pyramids onto facets, without losing the convexity throughout the
process? We prove that this is indeed possible for (i) 3-polytopes, (ii)
4-polytopes under a certain infinitesimal quasi-pyramidal relaxation, and (iii)
all dimensions asymptotically. The motivation partly comes from our study of
K-theory of monoid rings and of certain posets of discrete-convex objects.

Combinatorics;Metric Geometry