clust.dot   [plain text]

digraph G {
	subgraph cluster_0 {
		label = "hello world";
		a -> b;
		a -> c;
		color = hot_pink;
	}

	subgraph cluster_1 {
		label = "MSDOT";
		style= "dashed";
		color=purple;
		x -> y;
		x -> z;
		y -> z;
		y -> q;
	}

	top -> a;
	top -> y;
	y -> b;
}