Move towards replacing F.foldM with streaming, using mutable accumulator

src/Polyhedra.hs

@@ -88,7 +88,7 @@ polyToPics = map helpPoly3D . _pyFaces
 helpPoly3D :: [(Point3, Point4)] -> [Verx]
 helpPoly3D vs = map f $ polyToTris vs
   where
-    f (pos,col) = Verx pos col PolyV 0
+    f (pos,col) = Verx pos col PolyV 0 polyNum
 
 polysToPic :: [Polyhedra] -> Picture
 polysToPic = pictures . concatMap polyToPics