In 1992 Khovanski and Pukhlikov introduced certain integer-valued constructible functions on a real vector space which generalize the characteristic functions of convex polytope. They extended the Minkowski sum to the algebra structure on these "virtual" polytopes. One can naturally replace the constructible function by a constructible sheaf and try to define the products on the chain level. I will explain some combinatorial aspects of the problem. This is an episode in a larger project with Gabe Kerr (in progress) to relate Matrix factorizations to the Fukaya category of affine hypersurfaces.