 0, 0,
          1, 0, 0,
          1, 0, 0,
          1, 0, 0,
          1, 0, 0,

          // bottom of middle rung.
          0, -1, 0,
          0, -1, 0,
          0, -1, 0,
          0, -1, 0,
          0, -1, 0,
          0, -1, 0,

          // right of bottom
          1, 0, 0,
          1, 0, 0,
          1, 0, 0,
          1, 0, 0,
          1, 0, 0,
          1, 0, 0,

          // bottom
          0, -1, 0,
          0, -1, 0,
          0, -1, 0,
          0, -1, 0,
          0, -1, 0,
       