Shaded Zendala

I am reposting my recent Zendala.  Returning to my blog and looking at this Zendala I knew it did not look right, but what was wrong with it?  Huh, the Zendala had no shading on it.  Well, I shaded the tile and you can see the difference between the two.  The unshaded Zendala is below the shaded tile.  Take a look, see the difference shading can make on a design.