dont stroke; fill!

waves.py

@@ -59,14 +59,10 @@ def main():
         ctx.move_to(*points[0])
         for p in points[1:]:
             ctx.line_to(*p)
-        ctx.set_line_width(step_size)  #0.002)
-        ctx.stroke()
-        # fill area above
-        ctx.set_line_width(step_size)
-        for pos in range(len(points)):
-            ctx.move_to(*points[pos])
-            ctx.line_to(*lastpoints[pos])
-            ctx.stroke()
+        for p in reversed(lastpoints):
+            ctx.line_to(*p)
+        ctx.line_to(*points[0])
+        ctx.fill()
         lastpoints = points