     // top rung front
          30,   0,  0,
          30,  30,  0,
          100,   0,  0,
          30,  30,  0,
          100,  30,  0,
          100,   0,  0,

          // middle rung front
          30,  60,  0,
          30,  90,  0,
          67,  60,  0,
          30,  90,  0,
          67,  90,  0,
          67,  60,  0,

          // left column back
            0,   0,  30,
           30,   0,  30,
            0, 150,  30,
            0, 150,  30,
           30,   0,  30,
           30, 150,  3