diff --git a/ipynb/Life.ipynb b/ipynb/Life.ipynb
index 166ef79..0ac5a58 100644
--- a/ipynb/Life.ipynb
+++ b/ipynb/Life.ipynb
@@ -321,7 +321,7 @@
     "                         picture(world, Xs, Ys)), raw=True)\n",
     "        sleep(pause)\n",
     "        \n",
-    "def pre(text) -> str: return f'<{}pre>{text}</{}pre>'"
+    "def pre(text) -> str: return f'<{}pre>{text}<{}/pre>'"
    ]
   },
   {