digraph G
{
	graph
	[
		size = "6,6"
	]
	a -> b -> c
	subgraph cluster0
	{
		x0 -> y0
		x0 -> z0
	}
	subgraph cluster1
	{
		x1 -> y1
		x1 -> z1
	}
	subgraph cluster2
	{
		x2 -> y2
		x2 -> z2
	}
	a -> x0
	b -> x1
	b -> x2
	a -> z2
	c -> z1
}