diff --git a/Chapter 01/Chapter 01 Walkthrough.ipynb b/Chapter 01/Chapter 01 Walkthrough.ipynb
index dd21f0f..5015ff5 100644
--- a/Chapter 01/Chapter 01 Walkthrough.ipynb	
+++ b/Chapter 01/Chapter 01 Walkthrough.ipynb	
@@ -65,6 +65,10 @@
     "for delta in np.random.normal(0,0.5,500):\n",
     "    ys.append(ys[-1] + delta)\n",
     "    \n",
+    "# safely create the figures directory\n",
+    "from pathlib import Path\n",
+    "Path(\"figures\").mkdir(parents=True, exist_ok=True)\n",
+    "    \n",
     "plt.plot(ys)\n",
     "plt.ylabel('Stock Price ($)')\n",
     "plt.xlabel('Elapsed Time (min)')\n",
diff --git a/Chapter 03/draw3d.py b/Chapter 03/draw3d.py
index a6e19a4..d6ff2ef 100755
--- a/Chapter 03/draw3d.py	
+++ b/Chapter 03/draw3d.py	
@@ -16,7 +16,7 @@ def __init__(self, xs, ys, zs, *args, **kwargs):
 
     def draw(self, renderer):
         xs3d, ys3d, zs3d = self._verts3d
-        xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, renderer.M)
+        xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, self.axes.M)
         self.set_positions((xs[0],ys[0]),(xs[1],ys[1]))
         FancyArrowPatch.draw(self, renderer)