Final: Add note about weirdness in 3.6.

Final/Final - Tight-binding propagation method.ipynb

@@ -1159,6 +1159,8 @@
     }
    ],
    "source": [
+    "# TODO: The shape of the last (n = 100) graph does not look similar enough in my opinion,\n",
+    "#       and n = 40 is weird.\n",
     "sigma = .005\n",
     "w = np.linspace(-.5, .5, 1000)\n",
     "\n",