diff --git a/talks/virtual_intro/intro.ipynb b/talks/virtual_intro/intro.ipynb
index b64e05951b474f579b4e8ed714d6f406970d45bb..9e6552da9bfdc2b67944af7256449cbc7e48a4d6 100644
--- a/talks/virtual_intro/intro.ipynb
+++ b/talks/virtual_intro/intro.ipynb
@@ -410,7 +410,9 @@
     "t2 = (t, l)\n",
     "l2 = [t, l]\n",
     "print('t2 is: ', t2)\n",
-    "print('l3 is: ', l2)"
+    "print('l3 is: ', l2)\n",
+    "print(len(t2))\n",
+    "print(len(l2))"
    ]
   },
   {
@@ -892,7 +894,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "<a class=\"anchor\" id=\" reading-and-writing-text-files\"></a>\n",
+    "<a class=\"anchor\" id=\"reading-and-writing-text-files\"></a>\n",
     "# Reading and writing text files\n",
     "\n",
     "\n",
@@ -1109,14 +1111,17 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "def changeList(l):\n",
+    "def changelist(l):\n",
     "   l[0] = 'mwahahaha!'\n",
     "\n",
     "mylist = [1,2,3,4,5]\n",
     "\n",
     "print('before:', mylist)\n",
     "changelist(mylist)\n",
-    "print('after:', mylist)"
+    "print('after:', mylist)\n",
+    "\n",
+    "mytup = [1,2,3,4,5]\n",
+    "changelist(mytup)"
    ]
   },
   {
@@ -1220,8 +1225,10 @@
     "xyz_coords = np.array([[-11.4,   1.0,  22.6],\n",
     "                       [ 22.7, -32.8,  19.1],\n",
     "                       [ 62.8, -18.2, -34.5]])\n",
-    "print('data:', data)\n",
-    "print('xyz_coords:', xyz_coords)"
+    "print('data:            ', data)\n",
+    "print('xyz_coords:      ', xyz_coords)\n",
+    "print('data.shape:      ', data.shape)\n",
+    "print('xyz_coords.shape:', xyz_coords.shape)"
    ]
   },
   {
diff --git a/talks/virtual_intro/intro.md b/talks/virtual_intro/intro.md
index 8d5499a21cfb5659697feb0e8d138818bacf3fa8..ae6feba4a44b1df274a62eb48dbcee07aa3b648e 100644
--- a/talks/virtual_intro/intro.md
+++ b/talks/virtual_intro/intro.md
@@ -311,6 +311,8 @@ t2 = (t, l)
 l2 = [t, l]
 print('t2 is: ', t2)
 print('l3 is: ', l2)
+print(len(t2))
+print(len(l2))
 ```
 
 
@@ -628,7 +630,7 @@ for s, c in nchars.items():
 ```
 
 
-<a class="anchor" id=" reading-and-writing-text-files"></a>
+<a class="anchor" id="reading-and-writing-text-files"></a>
 # Reading and writing text files
 
 
@@ -784,7 +786,7 @@ might change it!
 
 
 ```
-def changeList(l):
+def changelist(l):
    l[0] = 'mwahahaha!'
 
 mylist = [1,2,3,4,5]
@@ -792,6 +794,9 @@ mylist = [1,2,3,4,5]
 print('before:', mylist)
 changelist(mylist)
 print('after:', mylist)
+
+mytup = [1,2,3,4,5]
+changelist(mytup)
 ```
 
 
@@ -871,8 +876,10 @@ data = np.array([10, 8, 12, 14, 7, 6, 11])
 xyz_coords = np.array([[-11.4,   1.0,  22.6],
                        [ 22.7, -32.8,  19.1],
                        [ 62.8, -18.2, -34.5]])
-print('data:', data)
-print('xyz_coords:', xyz_coords)
+print('data:            ', data)
+print('xyz_coords:      ', xyz_coords)
+print('data.shape:      ', data.shape)
+print('xyz_coords.shape:', xyz_coords.shape)
 ```