digraph abbildung1 {
{
a,b,c,d [shape=circle]
e,f,g,h [shape=polygon]
i,j,k,l [shape=diamond]
}
a -> {b,c,d} [dir=none];
b -> {c,d} [dir=none];
c -> {d} [dir=none];
e -> {f} [dir=none];
i -> {e,f,g,h,j,l} [dir=none];
j -> {l} [dir=none];
g -> {h} [dir=none];
}