On one of my FW tanks, I cut some flagstone with a 90 degree corner and siliconed it to the front corners so there were ledges about 2/3 of the way up the front. and some pieces I cut with a straight edge and glued to the back. It looks pretty cool, sorry no pics. I recommend black silicone. Has held for 5 years. I used about 3 soda bottles to hold the ledges level while it cured.