diff --git a/tricco/cubulation_functions.py b/tricco/cubulation_functions.py
index 1abc9d4dd379dbf35c4e762144906c00be47fa86..344cd65a2d85599deb85c94496c30637b446e272 100644
--- a/tricco/cubulation_functions.py
+++ b/tricco/cubulation_functions.py
@@ -142,13 +142,12 @@ def cubing_next_round(cube_coordinates, visited_triangles, outmost, edge_colours
     
     # list for triangles that will be outmost in next iteration
     new_outmost = []
-    
+   
     for old in outmost: # consider all EnhancedTri's at the border of visited
         for neigh in get_neighbors_of_cell(old.triangle ): # consider all neighbours
             new = EnhancedTri(neigh, 0)
-            if new.triangle == -9999: # use feature: triangles at the grid border claim to be adjacent to -9999
-                break
-            else:
+
+            if new.triangle != -9999: # ommit missing triangles that occur at the grid border (marked by -9999)
                 if new.triangle not in visited_triangles: # EnhancedTri new has no cube_coordinate yet
 
                     # add new to new_outmost for next round hereafter and update visited_triangles