code: protected void findClusters() {
  
  		for (int i = 0; i < nodes.size(); i++) {
  			SquareNode n = nodes.get(i);
  
  			if( n.graph < 0 ) {
  				n.graph = clusters.size();
  				List<SquareNode> graph = clusters.grow();
  				graph.add(n);
  				addToCluster(n, graph);
  			}
  		}
  	}
docs: Put sets of nodes into the same list if they are some how connected