strict digraph Seq { { //HEADING rank=same a [label="a"] ; b [label="b"] ; c [label="c"] ; d [label="d"] ; } { //tier1 rank=same; tier1 [style=invis,shape=point] ; a1 [style=invis,shape=point] ; b1 [style=invis,shape=point] ; } { //tier2 rank=same; tier2 [style=invis,shape=point] ; b2 [style=invis,shape=point] ; c1 [style=invis,shape=point] ; } { //tier3 rank=same; tier3 [style=invis,shape=point] ; c2 [style=filled,shape=plaintext,label="3: what to do\nnext?"] ; } { //tier4 rank=same; tier4 [style=invis,shape=point] ; c3 [style=invis,shape=point] ; a2 [style=invis,shape=point] ; } { //tier5 rank=same; tier5 [style=invis,shape=point] ; a3 [style=filled,shape=plaintext,label="5: not fair!"] ; } { //tier6 rank=same; tier6 [style=invis,shape=point] ; a4 [style=invis,shape=point] ; c4 [style=invis,shape=point] ; } { //tier7 rank=same; tier7 [style=invis,shape=point] ; c5 [style=invis,shape=point] ; d1 [style=invis,shape=point] ; } { //tier8 rank=same; tier8 [style=invis,shape=point] ; d2 [style=filled,shape=plaintext,label="8: zZzZzZzZzzz...."] ; } a -> a1 [style=dotted,arrowhead=none] ; b -> b1 [style=dotted,arrowhead=none] ; a1 -> b1 [label="1: catch a ball!",constraint=false] ; b1 -> b2 [style=dotted,arrowhead=none] ; c -> c1 [style=dotted,arrowhead=none] ; b2 -> c1 [label="2: i'll pass it\nalong",constraint=false] ; tier1 -> tier2 [style=invis] ; c1 -> c2 [style=dotted,arrowhead=none] ; tier2 -> tier3 [style=invis] ; c2 -> c3 [style=dotted,arrowhead=none] ; a1 -> a2 [style=dotted,arrowhead=none] ; c3 -> a2 [label="4: lets throw it\nback again",constraint=false] ; tier3 -> tier4 [style=invis] ; a2 -> a3 [style=dotted,arrowhead=none] ; tier4 -> tier5 [style=invis] ; a3 -> a4 [style=dotted,arrowhead=none] ; c3 -> c4 [style=dotted,arrowhead=none] ; a4 -> c4 [label="6: find someone else!",constraint=false] ; tier5 -> tier6 [style=invis] ; c4 -> c5 [style=dotted,arrowhead=none] ; d -> d1 [style=dotted,arrowhead=none] ; c5 -> d1 [label="7: ok, here you\ngo",constraint=false] ; tier6 -> tier7 [style=invis] ; d1 -> d2 [style=dotted,arrowhead=none] ; tier7 -> tier8 [style=invis] ; }