revert changes to cube.ipynb

Author: emilk

examples/python/notebook/cube.ipynb

@@ -177,7 +177,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-       "\n",
+     "\n",
     "STEPS = 100\n",
     "twists = math.pi * np.sin(np.linspace(0, math.tau, STEPS)) / 4\n",
     "for t in range(STEPS):\n",