diff --git a/bind/example.ipynb b/bind/example.ipynb
index 83f2b46..8545ce0 100644
--- a/bind/example.ipynb
+++ b/bind/example.ipynb
@@ -10,12 +10,12 @@
     "\n",
     "gd = GeometryDescriptor() #the width of the calorimeter is 50 cm times 50 cm (also steerable, but I'd leave it)\n",
     "\n",
-    "gd.addLayer(3,\"G4_Si\",True, 7)\n",
     "gd.addLayer(4,\"G4_Pb\",False) \n",
-    "gd.addLayer(3,\"G4_Si\",True, 7)\n",
+    "gd.addLayer(3,\"G4_POLYSTYRENE\",True, 7)\n",
+    "gd.addLayer(4,\"G4_Pb\",False) \n",
+    "gd.addLayer(3,\"G4_POLYSTYRENE\",True, 7)\n",
     "gd.addLayer(4,\"G4_Pb\",False)\n",
-    "gd.addLayer(3,\"G4_Si\",True, 7)\n",
-    "gd.addLayer(4,\"G4_Pb\",False)"
+    "gd.addLayer(3,\"G4_POLYSTYRENE\",True, 7)"
    ]
   },
   {