edges add rtarrowedline new head rtfilleddiamond ashead color color black width 2 attachpoint rtrectangleattachpoint new offset 15 edgefrom b1 to b2 .
edges add rtarrowedline new head rtfilleddiamond ashead color color black width 2 attachpoint rtrectangleattachpoint new offset 15 edgefrom b1 to b2 . | RTLineDecorationExample