My sample graph
+--------+ Test label +-------+ +-------+
#=====> | Five | - - - - - - > | Seven | | Eight |
H +--------+ +-------+ +-------+
H
H
H
H
#==================================#
v
+-----+ +--------+ +-------+ Test label +-------+
| Two | | One | ============> | Three | <............> | Six |
+-----+ +--------+ +-------+ +-------+
:
: Test
: label
v
+--------+
| Four |
+--------+