digraph G
{
subgraph cluster_c0
{
a0 -> a1 -> a2 -> a3
}
subgraph cluster_c1
{
b0 -> b1 -> b2 -> b3
}
x -> a0
x -> b0
a1 -> b3
b3 -> a1
}
digraph G
{
subgraph cluster_c0
{
a0 -> a1 -> a2 -> a3
}
subgraph cluster_c1
{
b0 -> b1 -> b2 -> b3
}
x -> a0
x -> b0
a1 -> b3
b3 -> a1
}