, height: 6, portId: "A", toSpot: go.Spot.Left,
                    toLinkable: true, toMaxLinks: 1 }),  // allow user-drawn links to here
                new go.TextBlock( "A")  // "A" port label
              ),
            new go.Panel("Horizontal",
              { column: 0, row: 2 })
              .add(
                new go.Shape( // the "B" port
                  { width: 6, height: 6, portId: "B", toSpot: go.Spot.Left,
                    toLinkable: true, toMaxLinks: 1 }),  // allow user-drawn lin