  Let $N$ be a lattice of rank $n$ and let $M = N^{\vee}$ be its dual lattice.
In this note we show that given two compact, bounded, full-dimensional convex
sets $K_1 \subseteq K_2 \subseteq M_{\R} \coloneqq M \otimes_{\Z} \R$, there is
a canonical convex decomposition of the difference $K_2 \setminus K_1$ and we
interpret the volume of the pieces geometrically in terms of intersection
numbers of toric $b$-divisors.
