Pisa II NATURAL ROCK FACE FINISH IN CURVED AND STRAIGHT LINES Modular units interlock with built in setback and automatically form correct slope, ensuring stable walls up to 4 feet from grade. Precast concrete units can be butted tight or placed with spacing for plant growth. Pisa II is supplied in rectangular as well as wedge-shaped units. The wedges, when placed together, help to form curved walls with continuous tight fit. Units can be placed around inside curves with spaces left at the rear being filled with granular draining material. Staggered blocks in successive courses maintain the interlock. Pisa II is supplied in twin modules with a splitting groove molded in. Easy breakage with a hammer and chisel produces the fresh cut finish. Coping - A straight wall is capped with Pisa Stone coping. Various degrees of curve can be accommodated by using Revers-a-Cap coping. All coping for Pisa II walls must be secured with a butyl tape or Paver Bond adhesive.