How to cut retaining wall coping for a curved wall: 1. Lay the first cap on the wall at the desired angle (split off any exposed edges that should match the factory split face) 2. Place the second cap on the wall up against the first and adjust the angle of the face of the block to match the curve of the wall. Tip: if you overhang your caps, use your hands to feel underneath and match how much overhang is on both sides of the cap to get an angle that matches the wall. 3. Measure the widest part