diff --git a/floorshapes.cpp b/floorshapes.cpp
index 54242156..3b478973 100644
--- a/floorshapes.cpp
+++ b/floorshapes.cpp
@@ -685,6 +685,12 @@ void geometry_information::generate_floorshapes() {
     int n = isize(c.shapes);
     vector<cell> models(n);
     vector<heptagon> modelh(n);
+    for(int i=0; i<n; i++) {
+      auto &ms = models[i];
+      auto &mh = modelh[i];
+      for(auto& t: ms.c.move_table) t = nullptr;
+      for(auto& t: mh.c.move_table) t = nullptr;
+      }
     for(int i=0; i<n; i++) {
       auto &ms = models[i];
       auto &mh = modelh[i];