diff --git a/nbs/3. Background Removal with Robust PCA.ipynb b/nbs/3. Background Removal with Robust PCA.ipynb
index 16e49e8..e8558c3 100644
--- a/nbs/3. Background Removal with Robust PCA.ipynb	
+++ b/nbs/3. Background Removal with Robust PCA.ipynb	
@@ -1199,7 +1199,7 @@
     "        Z = X - L - S\n",
     "        Y += mu*Z; mu *= rho\n",
     "        \n",
-    "        examples.extend([S[140,:], L[140,:]])\n",
+    "        examples.extend([S[:,140], L[:,140]])\n",
     "        \n",
     "        if m > mu_bar: m = mu_bar\n",
     "        if converged(Z, d_norm): break\n",