add(
                      // the main path of the graduated panel, an arc starting at 135 degrees and sweeping for 270 degrees
                      new go.Shape({
                        name: 'PATH',
                        geometryString: 'M-70.7107 70.7107 B135 270 0 0 100 100 M0 100',
                        stroke: 'white',
                        strokeWidth: 4
                      }),
                      // three differently sized tick marks
                      new go.Shape({ geometryString: '