Make Placement into a product type

src/Dodge/Placement/Instance/LightSource.hs

@@ -155,13 +155,13 @@ mntLSCond shp ps =
 
 -- note that this perhaps pushes the vshape light out too far
 
-mntLight :: Point2 -> Point2 -> Placement
-mntLight a b = RandomPlacement $ do
+mntLight :: RandomGen g => Point2 -> Point2 -> State g Placement
+mntLight a b = do
     shp <- takeOne [vShape, iShape, lShape, jShape, liShape]
     return $ mntLS shp a (addZ 90 b)
 
-mntLightLnkCond :: PlacementSpot -> Placement
-mntLightLnkCond ps = RandomPlacement $ do
+mntLightLnkCond :: RandomGen g => PlacementSpot -> State g Placement
+mntLightLnkCond ps = do
     shp <- takeOne [vShape, lShape, jShape, liShape]
     return $ mntLSCond (fmap (fmap $ colorSH black) shp) ps