diff --git a/Exercise sheet 6/exercise_sheet_06.ipynb b/Exercise sheet 6/exercise_sheet_06.ipynb
index a75cfc7..738ac6c 100644
--- a/Exercise sheet 6/exercise_sheet_06.ipynb	
+++ b/Exercise sheet 6/exercise_sheet_06.ipynb	
@@ -257,7 +257,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 100,
+   "execution_count": 106,
    "id": "6e4a6d63",
    "metadata": {
     "deletable": false,
@@ -281,18 +281,19 @@
     "def xy_cluster_flip(state,seed,nhat,beta):\n",
     "    '''Perform a cluster move with specified seed and vector nhat on the state at temperature beta.'''\n",
     "    w = len(state)\n",
+    "    \n",
     "    # Let's flip along the way, starting with the seed.\n",
     "    state[seed] -= 2*state[seed]@nhat*nhat\n",
-    "    cluster_size = 1\n",
     "    # Use a double-ended queue to keep track of what elements to try to expand from.\n",
     "    unvisited = deque([seed])\n",
+    "    cluster_size = 1\n",
     "    while unvisited:\n",
     "        site = unvisited.pop()\n",
     "        s_i_n = -state[site]@nhat\n",
     "        for nbr in neighboring_sites(site,w):\n",
     "            s_j_n = state[nbr]@nhat\n",
     "            p_add = 1 - np.exp(-2*beta*s_i_n*s_j_n)\n",
-    "            if s_i_n*s_j_n > 0 and rng.uniform() < p_add:\n",
+    "            if np.sign(s_i_n) == np.sign(s_j_n) and rng.uniform() < p_add:\n",
     "                state[nbr] -= 2*s_j_n*nhat\n",
     "                unvisited.appendleft(nbr)\n",
     "                cluster_size += 1\n",
@@ -308,7 +309,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 101,
+   "execution_count": 107,
    "id": "3f810041",
    "metadata": {
     "deletable": false,
@@ -339,7 +340,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 102,
+   "execution_count": 108,
    "id": "bde560e4",
    "metadata": {
     "deletable": false,