The Cork Bark background is pieced together out of several pieces. I used an electric plainer to flatten the back of the cork before glueing it to the tank glass. Then I filled in the gaps/seams between the cork panels with spanish moss. The spanish moss has not held up that well, I think I would use coconut husk or spagnum moss if I were to do it again. I, also, siliconed a 1/4 curl into the corner to conceal the supply line and a return line (to the Eheim).