diff --git a/search.ipynb b/search.ipynb
index 238fd8228..cf3b4306e 100644
--- a/search.ipynb
+++ b/search.ipynb
@@ -36,6 +36,7 @@
     "\n",
     "* Overview\n",
     "* Problem\n",
+    "* Node\n",
     "* Search Algorithms Visualization\n",
     "* Breadth-First Tree Search\n",
     "* Breadth-First Search\n",
@@ -189,7 +190,9 @@
   {
    "cell_type": "code",
    "execution_count": 2,
-   "metadata": {},
+   "metadata": {
+    "collapsed": true
+   },
    "outputs": [],
    "source": [
     "romania_map = UndirectedGraph(dict(\n",
@@ -234,7 +237,9 @@
   {
    "cell_type": "code",
    "execution_count": 3,
-   "metadata": {},
+   "metadata": {
+    "collapsed": true
+   },
    "outputs": [],
    "source": [
     "romania_problem = GraphProblem('Arad', 'Bucharest', romania_map)"
@@ -284,7 +289,9 @@
   {
    "cell_type": "code",
    "execution_count": 5,
-   "metadata": {},
+   "metadata": {
+    "collapsed": true
+   },
    "outputs": [],
    "source": [
     "%matplotlib inline\n",
@@ -308,7 +315,9 @@
   {
    "cell_type": "code",
    "execution_count": 6,
-   "metadata": {},
+   "metadata": {
+    "collapsed": true
+   },
    "outputs": [],
    "source": [
     "# initialise a graph\n",
@@ -352,7 +361,9 @@
   {
    "cell_type": "code",
    "execution_count": 7,
-   "metadata": {},
+   "metadata": {
+    "collapsed": true
+   },
    "outputs": [],
    "source": [
     "# initialise a graph\n",
@@ -1358,7 +1369,9 @@
   {
    "cell_type": "code",
    "execution_count": 11,
-   "metadata": {},
+   "metadata": {
+    "collapsed": true
+   },
    "outputs": [],
    "source": [
     "# Heuristics for 8 Puzzle Problem\n",