my $id1 = $canvas->createLine(60, 60, 220, 240, 400, 400,
                              -smooth => 1,
                              -arrow => "first",
                              -arrowshape => [ 20, 20, 20]);
my $id2 = $canvas->createLine(60, 60, 220, 260, 400, 400,
                              -smooth => 1,
                              -arrow => "last",
                              -arrowshape => [ 20, 20, 20]);