diff --git a/src/main/java/codegen/analysis/dataflow/DataFlowGraph.java b/src/main/java/codegen/analysis/dataflow/DataFlowGraph.java
index e0a970f..4b7f3c0 100644
--- a/src/main/java/codegen/analysis/dataflow/DataFlowGraph.java
+++ b/src/main/java/codegen/analysis/dataflow/DataFlowGraph.java
@@ -116,8 +116,8 @@ public final class DataFlowGraph implements Iterable<DataFlowNode> {
                .append("}\"];\n");
         }
 
-        dot.append("START[label=\"START\"];\n")
-           .append("END[label=\"END\"];\n");
+        dot.append("START[label=\"START\" shape=box];\n")
+           .append("END[label=\"END\" shape=box];\n");
 
         dot.append("START -> \"").append(this.dataFlowNodes.get(0).getId()).append("\";\n");
         dot.append("\"").append(this.dataFlowNodes.get(this.dataFlowNodes.size() - 1).getId()).append("\" -> END;\n");
@@ -129,6 +129,16 @@ public final class DataFlowGraph implements Iterable<DataFlowNode> {
             }
         }
 
+        for (DataFlowNode node : this.dataFlowNodes) {
+            dot.append("{ rank=same; ");
+            for (DataFlowNode successor : node.getSuccessorSet()) {
+
+                dot.append("\"").append(successor.getId()).append("\", ");
+            }
+            dot.deleteCharAt(dot.lastIndexOf(","));
+            dot.append("}\n");
+        }
+
         dot.append("}");
 
         GraphvizCaller.callGraphviz(dot, "DataFlowGraph");
diff --git a/src/main/java/codegen/flowgraph/FlowGraph.java b/src/main/java/codegen/flowgraph/FlowGraph.java
index 45970d9..8632f3d 100644
--- a/src/main/java/codegen/flowgraph/FlowGraph.java
+++ b/src/main/java/codegen/flowgraph/FlowGraph.java
@@ -204,10 +204,6 @@ public class FlowGraph implements Iterable<FlowBasicBlock> {
     public String printToImage() {
         final Optional<FlowBasicBlock> currentBlock = this.getCurrentBlock();
 
-        if (this.basicBlocks.isEmpty() || currentBlock.isEmpty()) {
-            return "Can't export empty graph: FlowGraph.svg";
-        }
-
         final StringBuilder dot = new StringBuilder();
 
         dot.append("digraph dfd {\n")
@@ -225,18 +221,36 @@ public class FlowGraph implements Iterable<FlowBasicBlock> {
                .append("}\"];\n");
         }
 
-        dot.append("START[label=\"START\"];\n")
-           .append("END[label=\"END\"];\n");
+        dot.append("START[label=\"START\" shape=box];\n")
+           .append("END[label=\"END\" shape=box];\n");
 
-        dot.append("START -> \"").append(this.basicBlocks.get(0).getId()).append("\";\n");
-        dot.append("\"").append(currentBlock.get().getId()).append("\" -> END;\n");
 
-        for (FlowBasicBlock block : this.basicBlocks) {
-            // Successors
+        if (!this.basicBlocks.isEmpty() && currentBlock.isPresent()) {
 
-            for (FlowBasicBlock successor : block.getBlockSuccessorSet()) {
-                dot.append("\"").append(block.getId()).append("\" -> \"").append(successor.getId()).append("\";\n");
+            dot.append("START -> \"").append(this.basicBlocks.get(0).getId()).append("\";\n");
+            dot.append("\"").append(currentBlock.get().getId()).append("\" -> END;\n");
+
+            for (FlowBasicBlock block : this.basicBlocks) {
+                // Successors
+
+                for (FlowBasicBlock successor : block.getBlockSuccessorSet()) {
+                    dot.append("\"").append(block.getId()).append("\" -> \"").append(successor.getId()).append("\";\n");
+                }
             }
+
+            for (FlowBasicBlock block : this.basicBlocks) {
+                dot.append("{ rank=same; ");
+                for (FlowBasicBlock successor : block.getBlockSuccessorSet()) {
+
+                    dot.append("\"").append(successor.getId()).append("\", ");
+                }
+                dot.deleteCharAt(dot.lastIndexOf(","));
+                dot.append("}\n");
+            }
+        } else {
+            // Main-method is empty
+
+            dot.append("START -> END");
         }
 
         dot.append("}");
diff --git a/src/main/java/parser/ast/SyntaxTree.java b/src/main/java/parser/ast/SyntaxTree.java
index e53560d..097809a 100644
--- a/src/main/java/parser/ast/SyntaxTree.java
+++ b/src/main/java/parser/ast/SyntaxTree.java
@@ -67,9 +67,15 @@ public class SyntaxTree {
 
             dot.append("\"").append(current.getId()).append("\"")
                .append(" [label=\"{<f0> ")
-               .append(current.getName())
+               .append(current.getName()
+                              .replace("\"", "\\\"")
+                              .replace("<", "less")
+                              .replace(">", "greater"))
                .append("|<f1> ")
-               .append(current.getValue())
+               .append(current.getValue()
+                              .replace("\"", "\\\"")
+                              .replace("<", "less")
+                              .replace(">", "greater"))
                .append("}\"];\n");
 
             current.getChildren().forEach(stack::push);