foozy@708: digraph undo_non_tip {
foozy@708: 	"first change" -> "second change";
foozy@708: 	"second change" -> "third change";
foozy@708: 	backout [label="back out\nsecond change", shape=box];
foozy@708: 	"second change" -> backout;
foozy@708: 	merge [label="automated\nmerge", shape=box];
foozy@708: 	"third change" -> merge;
foozy@708: 	backout -> merge;
foozy@708: }