Make anti-clockwise what were clockwise shapes, cleanup flash module-ing

src/Shape.hs

@@ -55,6 +55,7 @@ polyCircx n = map (vNormaly . addZ 0) . polyCirc n
 -- length of polys must be the same
 -- points should be correctly ordered so that
 -- polys form a prism-like object with quad faces between them
+-- each layer of points must be arranged anticlockwise
 prismPoly ::
     Size ->
     Importance ->
@@ -123,6 +124,7 @@ upperPrismPoly ::
     Size ->
     Importance ->
     Float ->
+    -- | Should be anticlockwise
     [Point2] ->
     Shape
 {-# INLINE upperPrismPoly #-}