diff --git a/addition_node.h b/addition_node.h
index 3639c7098..7c7d1cecc 100644
--- a/addition_node.h
+++ b/addition_node.h
@@ -44,10 +44,10 @@ public:
   }
 
   int numberOfChildren() const override { return m_numberOfChildren; }
-  void incrementNumberOfChildren() override { m_numberOfChildren++; }
-  void decrementNumberOfChildren() override {
+  void incrementNumberOfChildren(int increment = 1) override { m_numberOfChildren+= increment; }
+  void decrementNumberOfChildren(int decrement = 1) override {
     assert(m_numberOfChildren > 0);
-    m_numberOfChildren--;
+    m_numberOfChildren-= decrement;
   }
   void eraseNumberOfChildren() override {
     m_numberOfChildren = 0;
diff --git a/expression_node.h b/expression_node.h
index 444fc17ba..d0e45c238 100644
--- a/expression_node.h
+++ b/expression_node.h
@@ -8,7 +8,8 @@ public:
    enum class Type : uint8_t {
     AllocationFailure = 0,
     Float = 1,
-    Addition
+    Addition,
+    SimplificationRoot
    };
 
   // Expression
diff --git a/horizontal_layout_node.h b/horizontal_layout_node.h
index f412b20d8..53d332976 100644
--- a/horizontal_layout_node.h
+++ b/horizontal_layout_node.h
@@ -17,10 +17,10 @@ public:
   }
 
   int numberOfChildren() const override { return m_numberOfChildren; }
-  void incrementNumberOfChildren() override { m_numberOfChildren++; }
-  void decrementNumberOfChildren() override {
+  void incrementNumberOfChildren(int increment = 1) override { m_numberOfChildren+= increment; }
+  void decrementNumberOfChildren(int decrement = 1) override {
     assert(m_numberOfChildren > 0);
-    m_numberOfChildren--;
+    m_numberOfChildren-= decrement;
   }
   void eraseNumberOfChildren() override {
     m_numberOfChildren = 0;
diff --git a/refs.h b/refs.h
index 7135baceb..b5892885b 100644
--- a/refs.h
+++ b/refs.h
@@ -1,6 +1,7 @@
 #include "addition_node.h"
 #include "allocation_failed_expression_node.h"
 #include "float_node.h"
+#include "simplification_root_node.h"
 
 #include "char_layout_node.h"
 #include "horizontal_layout_node.h"
diff --git a/test.cpp b/test.cpp
index 98fdaeaa2..cd43a074b 100644
--- a/test.cpp
+++ b/test.cpp
@@ -232,7 +232,7 @@ void testSimplify() {
       FloatRef(2.0f));
 
   assert_expression_approximates_to(a, 3);
-
+  SimplificationRootRef b(a);
   a.deepReduce();
 
   assert_expression_approximates_to(a, 3);
@@ -277,7 +277,8 @@ int main() {
   runTest(testPoolExpressionAllocationFail);
   runTest(testPoolExpressionAllocationFail2);
   runTest(testPoolExpressionAllocationFailOnImbricatedAdditions);
-  //runTest(testStealOperand);
+  runTest(testStealOperand);
+  runTest(testSimplify);
   printf("\n*******************\nEnd of tests\n*******************\n\n");
   return 0;
 }
diff --git a/tree_node.h b/tree_node.h
index 1bf1de357..0d73a11bd 100644
--- a/tree_node.h
+++ b/tree_node.h
@@ -51,8 +51,8 @@ public:
   TreeNode * parentTree() const;
   TreeNode * editableRootTree();
   virtual int numberOfChildren() const = 0;
-  virtual void incrementNumberOfChildren() {} //TODO Put an assert false
-  virtual void decrementNumberOfChildren() {} //TODO Put an assert false //TODO what if somebody i stealing a unary tree's only child ?
+  virtual void incrementNumberOfChildren(int increment = 1) {} //TODO Put an assert false
+  virtual void decrementNumberOfChildren(int decrement = 1) {} //TODO Put an assert false //TODO what if somebody i stealing a unary tree's only child ?
   virtual void eraseNumberOfChildren() {} //TODO Put an assert false //TODO what if somebody i stealing a unary tree's only child ?
   int numberOfDescendants(bool includeSelf) const;
   TreeNode * childTreeAtIndex(int i) const;
diff --git a/tree_pool.h b/tree_pool.h
index 0ae8bf3c1..11d8c71de 100644
--- a/tree_pool.h
+++ b/tree_pool.h
@@ -141,7 +141,7 @@ private:
   // Pool memory
   void * alloc(size_t size);
   void dealloc(TreeNode * ptr);
-  static inline bool insert(char * destination, char * source, size_t length);
+  bool insert(char * destination, char * source, size_t length);
   void moveNodes(TreeNode * source, TreeNode * destination, size_t moveLength);
 
   // Identifiers
diff --git a/tree_reference.h b/tree_reference.h
index 55223f73c..a9c25bde2 100644
--- a/tree_reference.h
+++ b/tree_reference.h
@@ -61,8 +61,8 @@ public:
   bool isAllocationFailure() const { return node()->isAllocationFailure(); }
 
   int nodeRetainCount() const { return node()->retainCount(); }
-  void incrementNumberOfChildren() { return node()->incrementNumberOfChildren(); }
-  void decrementNumberOfChildren() { return node()->decrementNumberOfChildren(); }
+  void incrementNumberOfChildren(int increment = 1) { return node()->incrementNumberOfChildren(increment); }
+  void decrementNumberOfChildren(int decrement = 1) { return node()->decrementNumberOfChildren(decrement); }
 
   operator TreeReference<TreeNode>() const {
     return TreeReference<TreeNode>(this->node());
@@ -209,11 +209,14 @@ public:
 
   void mergeChildren(TreeReference<T> t) {
     // Steal operands
-    TreePool::sharedPool()->moveChildren(t.node(), node()->lastDescendant());
+    int numberOfNewChildren = t.numberOfChildren();
+    TreePool::sharedPool()->moveChildren(t.node(), node()->lastDescendant()->next());
+    t.node()->eraseNumberOfChildren();
     // If t is a child, remove it
     if (node()->hasChild(t.node())) {
       removeChild(t);
     }
+    node()->incrementNumberOfChildren(numberOfNewChildren);
   }
 
 protected: