Back wall anchored

I was going for a large cement block look.  The material for the back wall is regular dry wall. I used a screen repair tool(used to push the rubber straind into the frame to hold the screen) to make the grooves in the wall. 

  Looks like you have accomplished the large cement block look.  Very precise lines.  Thanks for sharing the material, tool and technique used to achieve this look.

Thank you...for as simple as it looks, it took quite a bit of work to get it there.