fact: Definition extend_grect p r := let: (Grect x0 x1 y0 y1, Gpoint x y) := (r, p) in Grect (Num.min x0 x) (Num.max x1 (x + 1)) (Num.min y0 y) (Num.max y1 (y + 1)).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(div choice order ssralg ssrnum ssrint intdiv) fourcolor(hypermap)