diff --git a/src/main/java/grafos/CFG.java b/src/main/java/grafos/CFG.java
index f3d1a5a..add3188 100644
--- a/src/main/java/grafos/CFG.java
+++ b/src/main/java/grafos/CFG.java
@@ -29,7 +29,7 @@ public class CFG {
 	}
 
 	public void beginBlock(Node node, Node condition, boolean addNow) {
-		Block b = new Block(node, condition, this);
+		Block b = new Block(node, condition);
 		if (condition != null && addNow)
 			addNode(condition);
 		if (blockStack.isEmpty())
@@ -48,7 +48,7 @@ public class CFG {
 	}
 
 	public void connect(Node begin, Node end) {
-		edges.add(new Edge(this, begin, end, nextLabel));
+		edges.add(new Edge(begin, end, nextLabel));
 		nextLabel = null;
 	}
 
@@ -101,17 +101,15 @@ public class CFG {
 				+ s.toString().replace("\"", "\\\"") + "\"";
 	}
 
-	static class Block extends LinkedList<Node> {
-		private static int clusterId = 0;
+	private static int clusterId = 0;
 
+	class Block extends LinkedList<Node> {
 		private final Node container, condition;
-		private final CFG cfg;
 		private final List<Block> inners = new LinkedList<>();
 
-		Block(Node container, Node condition, CFG cfg) {
+		Block(Node container, Node condition) {
 			this.container = container;
 			this.condition = condition;
-			this.cfg = cfg;
 		}
 
 		void addSubBlock(Block block) {
@@ -123,14 +121,14 @@ public class CFG {
 			res.add(gv.start_subgraph(clusterId++));
 			res.add("label = \"" + getTitle() + "\"");
 			if (condition != null) {
-				res.add("node [ shape = rectangle ]; " + cfg.node2str(condition));
+				res.add("node [ shape = rectangle ]; " + node2str(condition));
 				res.add("node [ shape = ellipse ]");
 			}
 			for (Block b : inners) {
 				res.addAll(b.toStringList(gv));
 			}
 			for (Node n : this) {
-				res.add(cfg.node2str(n));
+				res.add(node2str(n));
 			}
 			res.add(gv.end_subgraph());
 			return res;
@@ -173,20 +171,18 @@ public class CFG {
 		}
 	}
 
-	static class Edge {
-		private final CFG cfg;
+	class Edge {
 		private final Node origin, destination;
 		private final String label;
 
-		Edge(CFG cfg, Node origin, Node destination, String label) {
-			this.cfg = cfg;
+		Edge(Node origin, Node destination, String label) {
 			this.origin = origin;
 			this.destination = destination;
 			this.label = label;
 		}
 
 		public String toString() {
-			String s = cfg.node2str(origin) + " -> " + cfg.node2str(destination);
+			String s = node2str(origin) + " -> " + node2str(destination);
 			if (label != null) {
 				s += " [ label = \"" + label + "\" ]";
 			}