digraph  {
	subgraph cluster_s2 {
		label="Cluster A";
		n3[label="one"];
		n4[label="two"];
		
	}
	subgraph cluster_s5 {
		label="Cluster B";
		n7[label="four"];
		n6[label="three"];
		
	}
	
	n1[label="Outside"];
	n1->n7;
	n7->n3;
	n3->n4;
	n6->n1;
	n4->n6;
	
}
