Arranging the Surface

Next we produce a single graphics object with  eight copies of the computed patch. W do this by applying reflections to the patch. As some reflections reverse the orientation, we correct this by reversing the order of the points in the respective polygons:

First the reflection about the  y=x line:

Then the four copies obtained by reflecting about tbe coordinate planes:

If you don't want to see the grid edges:

Finally, here is an GLExplorer version: