diff --git a/src/db/db/dbAsIfFlatEdges.cc b/src/db/db/dbAsIfFlatEdges.cc
index 203a89e9f..209c303ae 100644
--- a/src/db/db/dbAsIfFlatEdges.cc
+++ b/src/db/db/dbAsIfFlatEdges.cc
@@ -533,7 +533,7 @@ EdgesDelegate *
 AsIfFlatEdges::boolean (const Edges *other, EdgeBoolOp op) const
 {
   std::auto_ptr<FlatEdges> output (new FlatEdges (true));
-  EdgeBooleanClusterCollector<db::Shapes> cluster_collector (&output->raw_edges (), op);
+  EdgeBooleanClusterCollectorToShapes cluster_collector (&output->raw_edges (), op);
 
   db::box_scanner<db::Edge, size_t> scanner (report_progress (), progress_desc ());
   scanner.reserve (size () + (other ? other->size () : 0));
diff --git a/src/db/db/dbBoxScanner.h b/src/db/db/dbBoxScanner.h
index 868ecc709..eefd7df5a 100644
--- a/src/db/db/dbBoxScanner.h
+++ b/src/db/db/dbBoxScanner.h
@@ -137,6 +137,21 @@ struct box_scanner_receiver
    *  terminate the scan process early if the outcome is known.
    */
   bool stop () const { return false; }
+
+  /**
+   *  @brief Pre-scanning operations
+   *
+   *  This method is called before the scanning starts.
+   */
+  void initialize () { }
+
+  /**
+   *  @brief Post-scanning operations
+   *
+   *  This method is called after the scan has finished (without exception). The argument is the
+   *  return value (false if "stop" stopped the process).
+   */
+  void finalize (bool) { }
 };
 
 /**
@@ -265,6 +280,22 @@ public:
    */
   template <class Rec, class BoxConvert>
   bool process (Rec &rec, typename BoxConvert::box_type::coord_type enl, const BoxConvert &bc = BoxConvert ())
+  {
+    rec.initialize ();
+    bool ret = do_process (rec, enl, bc);
+    rec.finalize (ret);
+    return ret;
+  }
+
+private:
+  container_type m_pp;
+  double m_fill_factor;
+  size_t m_scanner_thr;
+  bool m_report_progress;
+  std::string m_progress_desc;
+
+  template <class Rec, class BoxConvert>
+  bool do_process (Rec &rec, typename BoxConvert::box_type::coord_type enl, const BoxConvert &bc = BoxConvert ())
   {
     typedef typename BoxConvert::box_type box_type;
     typedef typename box_type::coord_type coord_type;
@@ -420,13 +451,6 @@ public:
     return true;
 
   }
-
-private:
-  container_type m_pp;
-  double m_fill_factor;
-  size_t m_scanner_thr;
-  bool m_report_progress;
-  std::string m_progress_desc;
 };
 
 /**
@@ -469,6 +493,21 @@ struct box_scanner_receiver2
    *  terminate the scan process early if the outcome is known.
    */
   bool stop () const { return false; }
+
+  /**
+   *  @brief Pre-scanning operations
+   *
+   *  This method is called before the scanning starts.
+   */
+  void initialize () { }
+
+  /**
+   *  @brief Post-scanning operations
+   *
+   *  This method is called after the scan has finished (without exception). The argument is the
+   *  return value (false if "stop" stopped the process).
+   */
+  void finalize (bool) { }
 };
 
 /**
@@ -613,6 +652,23 @@ public:
    */
   template <class Rec, class BoxConvert1, class BoxConvert2>
   bool process (Rec &rec, typename BoxConvert1::box_type::coord_type enl, const BoxConvert1 &bc1 = BoxConvert1 (), const BoxConvert2 &bc2 = BoxConvert2 ())
+  {
+    rec.initialize ();
+    bool ret = do_process (rec, enl, bc1, bc2);
+    rec.finalize (ret);
+    return ret;
+  }
+
+private:
+  container_type1 m_pp1;
+  container_type2 m_pp2;
+  double m_fill_factor;
+  size_t m_scanner_thr;
+  bool m_report_progress;
+  std::string m_progress_desc;
+
+  template <class Rec, class BoxConvert1, class BoxConvert2>
+  bool do_process (Rec &rec, typename BoxConvert1::box_type::coord_type enl, const BoxConvert1 &bc1 = BoxConvert1 (), const BoxConvert2 &bc2 = BoxConvert2 ())
   {
     typedef typename BoxConvert1::box_type box_type; //  must be same as BoxConvert2::box_type
     typedef typename box_type::coord_type coord_type;
@@ -845,14 +901,6 @@ public:
     return true;
 
   }
-
-private:
-  container_type1 m_pp1;
-  container_type2 m_pp2;
-  double m_fill_factor;
-  size_t m_scanner_thr;
-  bool m_report_progress;
-  std::string m_progress_desc;
 };
 
 /**
diff --git a/src/db/db/dbDeepEdges.cc b/src/db/db/dbDeepEdges.cc
index e0e11a055..e8929c7bf 100644
--- a/src/db/db/dbDeepEdges.cc
+++ b/src/db/db/dbDeepEdges.cc
@@ -349,7 +349,7 @@ public:
     //  .. and run the merge operation
 
     s->second.clear ();
-    EdgeBooleanClusterCollector<db::Shapes> cluster_collector (&s->second, EdgeOr);
+    EdgeBooleanClusterCollectorToShapes cluster_collector (&s->second, EdgeOr);
     m_scanner.process (cluster_collector, 1, db::box_convert<db::Edge> ());
 
     return s->second;
diff --git a/src/db/db/dbEdgeBoolean.h b/src/db/db/dbEdgeBoolean.h
index 449d3f8f1..a85fb6e40 100644
--- a/src/db/db/dbEdgeBoolean.h
+++ b/src/db/db/dbEdgeBoolean.h
@@ -26,6 +26,7 @@
 #include "dbEdge.h"
 #include "dbHash.h"
 #include "dbBoxScanner.h"
+#include "dbShapes.h"
 
 #include "tlIntervalMap.h"
 
@@ -222,14 +223,14 @@ struct EdgeBooleanClusterCollector
 {
   EdgeBooleanClusterCollector (OutputContainer *output, EdgeBoolOp op)
     : db::cluster_collector<db::Edge, size_t, EdgeBooleanCluster<OutputContainer> > (EdgeBooleanCluster<OutputContainer> (output, op == EdgeIntersections ? EdgeAnd : op), op != EdgeAnd && op != EdgeIntersections /*report single*/),
-      mp_intersections (op == EdgeIntersections ? output : 0)
+      mp_output (output), mp_intersections (op == EdgeIntersections ? output : 0)
   {
     //  .. nothing yet ..
   }
 
   EdgeBooleanClusterCollector (OutputContainer *output, OutputContainer *intersections, EdgeBoolOp op)
     : db::cluster_collector<db::Edge, size_t, EdgeBooleanCluster<OutputContainer> > (EdgeBooleanCluster<OutputContainer> (output, op), op != EdgeAnd /*report single*/),
-      mp_intersections (intersections)
+      mp_output (output), mp_intersections (intersections)
   {
     //  .. nothing yet ..
   }
@@ -252,16 +253,168 @@ struct EdgeBooleanClusterCollector
     } else if (mp_intersections && p1 != p2) {
 
       std::pair<bool, db::Point> ip = o1->intersect_point (*o2);
-      if (ip.first && m_seen_intersections.insert (ip.second).second) {
-        mp_intersections->insert (db::Edge (ip.second, ip.second));
+      if (ip.first) {
+        m_intersections.insert (ip.second);
       }
 
     }
   }
 
+  /**
+   *  @brief A receiver for the reducer which removes points that are on the edges
+   */
+  struct RemovePointsOnEdges
+    : public db::box_scanner_receiver2<db::Edge, size_t, db::Point, size_t>
+  {
+  public:
+    RemovePointsOnEdges (std::set<db::Point> &points_to_remove)
+      : mp_points_to_remove (&points_to_remove)
+    { }
+
+    void add (const db::Edge *e, const size_t &, const db::Point *pt, const size_t &)
+    {
+      if (e->contains (*pt)) {
+        mp_points_to_remove->insert (*pt);
+      }
+    }
+
+  private:
+    std::set<db::Point> *mp_points_to_remove;
+  };
+
+  /**
+   *  @brief An inserter to produce degenerated edges from points
+   */
+  struct PointInserter
+    : public std::iterator<std::output_iterator_tag, void, void, void, void>
+  {
+    typedef db::Point value_type;
+
+    PointInserter (OutputContainer *output)
+      : mp_output (output)
+    { }
+
+    PointInserter &operator= (const db::Point &pt)
+    {
+      mp_output->insert (db::Edge (pt, pt));
+      return *this;
+    }
+
+    PointInserter &operator* () { return *this; }
+    PointInserter &operator++ () { return *this; }
+    PointInserter &operator++ (int) { return *this; }
+
+  private:
+    OutputContainer *mp_output;
+  };
+
+  /**
+   *  @brief Finalizes the implementation for "EdgeIntersections"
+   *  This method pushes those points which don't interact with the edges to the output container
+   *  as degenerate edges. It needs to be called after the pass has been made.
+   */
+  void finalize (bool)
+  {
+    if (m_intersections.empty ()) {
+      return;
+    }
+
+    db::box_scanner2<db::Edge, size_t, db::Point, size_t> intersections_to_edge_scanner;
+    for (typename OutputContainer::const_iterator e = mp_output->begin (); e != mp_output->end (); ++e) {
+      intersections_to_edge_scanner.insert1 (e.operator-> (), 0);
+    }
+    for (std::set<db::Point>::const_iterator p = m_intersections.begin (); p != m_intersections.end (); ++p) {
+      intersections_to_edge_scanner.insert2 (p.operator-> (), 0);
+    }
+
+    std::set<db::Point> points_to_remove;
+    RemovePointsOnEdges rpoe (points_to_remove);
+    intersections_to_edge_scanner.process (rpoe, 1, db::box_convert<db::Edge> (), db::box_convert<db::Point> ());
+
+    std::set_difference (m_intersections.begin (), m_intersections.end (), points_to_remove.begin (), points_to_remove.end (), PointInserter (mp_intersections));
+  }
+
 private:
+  OutputContainer *mp_output;
   OutputContainer *mp_intersections;
-  std::unordered_set<db::Point> m_seen_intersections;
+  std::set<db::Point> m_intersections;
+};
+
+/**
+ *  @brief A helper class to use db::Shapes as container for EdgeBooleanClusterCollector
+ */
+struct DB_PUBLIC ShapesToOutputContainerAdaptor
+{
+public:
+  struct Iterator
+    : public db::Shapes::shape_iterator
+  {
+    Iterator (const db::Shapes::shape_iterator &iter)
+      : db::Shapes::shape_iterator (iter)
+    { }
+
+    Iterator ()
+      : db::Shapes::shape_iterator ()
+    { }
+
+    const db::Edge *operator-> () const
+    {
+      return (db::Shapes::shape_iterator::operator* ()).basic_ptr (db::Edge::tag ());
+    }
+
+    bool operator!= (const Iterator &other) const
+    {
+      //  only for testing whether at end:
+      return at_end () != other.at_end ();
+    }
+
+    bool operator== (const Iterator &other) const
+    {
+      //  only for testing whether at end:
+      return at_end () == other.at_end ();
+    }
+  };
+
+  typedef Iterator const_iterator;
+
+  ShapesToOutputContainerAdaptor (db::Shapes &shapes)
+    : mp_shapes (&shapes)
+  {
+    //  .. nothing yet ..
+  }
+
+  const_iterator begin ()
+  {
+    return Iterator (mp_shapes->begin (db::ShapeIterator::Edges));
+  }
+
+  const_iterator end ()
+  {
+    return Iterator ();
+  }
+
+  void insert (const db::Edge &edge)
+  {
+    mp_shapes->insert (edge);
+  }
+
+private:
+  db::Shapes *mp_shapes;
+};
+
+/**
+ *  @brief A specialization of the EdgeBooleanClusterCollector for a Shapes output container
+ */
+struct DB_PUBLIC EdgeBooleanClusterCollectorToShapes
+  : EdgeBooleanClusterCollector<ShapesToOutputContainerAdaptor>
+{
+  EdgeBooleanClusterCollectorToShapes (db::Shapes *output, EdgeBoolOp op)
+    : EdgeBooleanClusterCollector<ShapesToOutputContainerAdaptor> (&m_adaptor, op), m_adaptor (*output)
+  {
+  }
+
+private:
+  ShapesToOutputContainerAdaptor m_adaptor;
 };
 
 }
diff --git a/src/db/db/dbFlatEdges.cc b/src/db/db/dbFlatEdges.cc
index 75c977bee..75d80f539 100644
--- a/src/db/db/dbFlatEdges.cc
+++ b/src/db/db/dbFlatEdges.cc
@@ -112,7 +112,7 @@ FlatEdges::ensure_merged_edges_valid () const
     m_merged_edges.clear ();
 
     db::Shapes tmp (false);
-    EdgeBooleanClusterCollector<db::Shapes> cluster_collector (&tmp, EdgeOr);
+    EdgeBooleanClusterCollectorToShapes cluster_collector (&tmp, EdgeOr);
 
     db::box_scanner<db::Edge, size_t> scanner (report_progress (), progress_desc ());
     scanner.reserve (m_edges.size ());
diff --git a/src/db/db/dbHierNetworkProcessor.cc b/src/db/db/dbHierNetworkProcessor.cc
index 3c85dc9be..1728f32d6 100644
--- a/src/db/db/dbHierNetworkProcessor.cc
+++ b/src/db/db/dbHierNetworkProcessor.cc
@@ -1228,11 +1228,6 @@ public:
     add_pair (*c1, *i2, p, t);
   }
 
-  bool stop () const
-  {
-    return false;
-  }
-
   /**
    *  @brief Finally join the clusters in the join set
    *
@@ -1275,6 +1270,11 @@ public:
     }
   }
 
+  //  needs explicit implementation because we have two base classes:
+  bool stop () const { return false; }
+  void initialize () { }
+  void finalize (bool) { }
+
 private:
   struct InteractionKeyForClustersType
     : public InstanceToInstanceInteraction
diff --git a/src/db/db/dbOriginalLayerEdges.cc b/src/db/db/dbOriginalLayerEdges.cc
index ee47f5771..631652f8b 100644
--- a/src/db/db/dbOriginalLayerEdges.cc
+++ b/src/db/db/dbOriginalLayerEdges.cc
@@ -253,7 +253,7 @@ OriginalLayerEdges::ensure_merged_edges_valid () const
     m_merged_edges.clear ();
 
     db::Shapes tmp (false);
-    EdgeBooleanClusterCollector<db::Shapes> cluster_collector (&tmp, EdgeOr);
+    EdgeBooleanClusterCollectorToShapes cluster_collector (&tmp, EdgeOr);
 
     db::box_scanner<db::Edge, size_t> scanner (report_progress (), progress_desc ());
     scanner.reserve (size ());
diff --git a/src/db/unit_tests/dbBoxScanner.cc b/src/db/unit_tests/dbBoxScanner.cc
index 8d396e3b7..48369cb64 100644
--- a/src/db/unit_tests/dbBoxScanner.cc
+++ b/src/db/unit_tests/dbBoxScanner.cc
@@ -36,6 +36,8 @@ struct BoxScannerTestRecorder
   }
 
   bool stop () const { return false; }
+  void initialize () { str += "[i]"; }
+  void finalize (bool) { str += "[f]"; }
 
   void add (const db::Box * /*b1*/, size_t p1, const db::Box * /*b2*/, size_t p2)
   {
@@ -54,6 +56,8 @@ struct BoxScannerTestRecorderStopping
   }
 
   bool stop () const { return do_stop; }
+  void initialize () { str += "[i]"; }
+  void finalize (bool s) { str += s ? "[f+]" : "[f-]"; }
 
   void add (const db::Box * /*b1*/, size_t p1, const db::Box * /*b2*/, size_t p2)
   {
@@ -70,6 +74,8 @@ struct BoxScannerTestRecorder2
   void finish (const db::Box *, size_t) { }
 
   bool stop () const { return false; }
+  void initialize () { }
+  void finalize (bool) { }
 
   void add (const db::Box * /*b1*/, size_t p1, const db::Box * /*b2*/, size_t p2)
   {
@@ -91,6 +97,8 @@ struct BoxScannerTestRecorderTwo
   }
 
   bool stop () const { return false; }
+  void initialize () { str += "[i]"; }
+  void finalize (bool) { str += "[f]"; }
 
   void add (const db::Box * /*b1*/, size_t p1, const db::SimplePolygon * /*b2*/, int p2)
   {
@@ -113,6 +121,8 @@ struct BoxScannerTestRecorderTwoStopping
   }
 
   bool stop () const { return do_stop; }
+  void initialize () { str += "[i]"; }
+  void finalize (bool s) { str += s ? "[f+]" : "[f-]"; }
 
   void add (const db::Box * /*b1*/, size_t p1, const db::SimplePolygon * /*b2*/, int p2)
   {
@@ -130,6 +140,8 @@ struct BoxScannerTestRecorder2Two
   void finish2 (const db::SimplePolygon *, int) { }
 
   bool stop () const { return false; }
+  void initialize () { }
+  void finalize (bool) { }
 
   void add (const db::Box * /*b1*/, size_t p1, const db::SimplePolygon * /*b2*/, int p2)
   {
@@ -159,11 +171,11 @@ TEST(1)
   db::box_convert<db::Box> bc;
   bs.set_scanner_threshold (0);
   EXPECT_EQ (bs.process (tr, 1, bc), true);
-  EXPECT_EQ (tr.str, "(4-2)(5-2)(5-4)(3-2)(3-4)(5-3)<2><5><4><3>(1-0)<0><1>");
+  EXPECT_EQ (tr.str, "[i](4-2)(5-2)(5-4)(3-2)(3-4)(5-3)<2><5><4><3>(1-0)<0><1>[f]");
 
   BoxScannerTestRecorderStopping trstop;
   EXPECT_EQ (bs.process (trstop, 1, bc), false);
-  EXPECT_EQ (trstop.str, "(4-2)");
+  EXPECT_EQ (trstop.str, "[i](4-2)[f-]");
 }
 
 TEST(1a)
@@ -182,7 +194,7 @@ TEST(1a)
   db::box_convert<db::Box> bc;
   bs.set_scanner_threshold (0);
   bs.process (tr, 1, bc);
-  EXPECT_EQ (tr.str, "(1-0)<0><1>");
+  EXPECT_EQ (tr.str, "[i](1-0)<0><1>[f]");
 }
 
 TEST(1b)
@@ -204,7 +216,7 @@ TEST(1b)
   db::box_convert<db::Box> bc;
   bs.set_scanner_threshold (0);
   bs.process (tr, 1, bc);
-  EXPECT_EQ (tr.str, "(3-0)(1-3)(4-1)(2-4)<0><3><1><4><2>");
+  EXPECT_EQ (tr.str, "[i](3-0)(1-3)(4-1)(2-4)<0><3><1><4><2>[f]");
 }
 
 TEST(1c)
@@ -226,7 +238,7 @@ TEST(1c)
   db::box_convert<db::Box> bc;
   bs.set_scanner_threshold (0);
   bs.process (tr, 1, bc);
-  EXPECT_EQ (tr.str, "(3-0)(1-3)<0>(4-1)<3>(2-4)<1><4><2>");
+  EXPECT_EQ (tr.str, "[i](3-0)(1-3)<0>(4-1)<3>(2-4)<1><4><2>[f]");
 }
 
 TEST(1d)
@@ -248,7 +260,7 @@ TEST(1d)
   db::box_convert<db::Box> bc;
   bs.set_scanner_threshold (0);
   bs.process (tr, 0, bc);
-  EXPECT_EQ (tr.str, "(3-0)<0><3><1><4><2>");
+  EXPECT_EQ (tr.str, "[i](3-0)<0><3><1><4><2>[f]");
 }
 
 TEST(1e)
@@ -269,7 +281,7 @@ TEST(1e)
   bs.set_fill_factor (0.0);
   db::box_convert<db::Box> bc;
   bs.process (tr, 0, bc);
-  EXPECT_EQ (tr.str, "(0-3)<0><1><2><3><4>");
+  EXPECT_EQ (tr.str, "[i](0-3)<0><1><2><3><4>[f]");
 }
 
 TEST(1f)
@@ -280,7 +292,7 @@ TEST(1f)
   bs.set_fill_factor (0.0);
   db::box_convert<db::Box> bc;
   bs.process (tr, 0, bc);
-  EXPECT_EQ (tr.str, "");
+  EXPECT_EQ (tr.str, "[i][f]");
 }
 
 TEST(1g)
@@ -302,7 +314,7 @@ TEST(1g)
   bs.set_fill_factor (0.0);
   db::box_convert<db::Box> bc;
   bs.process (tr, 0, bc);
-  EXPECT_EQ (tr.str, "<2><4>(0-3)<0><1><3>");
+  EXPECT_EQ (tr.str, "[i]<2><4>(0-3)<0><1><3>[f]");
 }
 
 void run_test2 (tl::TestBase *_this, size_t n, double ff, db::Coord spread, bool touch = true)
@@ -927,7 +939,7 @@ TEST(two_1)
   db::box_convert<db::SimplePolygon> bc2;
   bs.set_scanner_threshold (0);
   bs.process (tr, 1, bc1, bc2);
-  EXPECT_EQ (tr.str, "(2-12)(2-14)(4-12)(4-14)(2-15)(4-15)(5-12)(5-14)(5-15)(2-13)(4-13)(3-12)(3-14)(3-13)(3-15)(5-13)(0-10)<2><5><4><3><12><15><14><13>(0-11)(1-10)(1-11)<0><1><10><11>");
+  EXPECT_EQ (tr.str, "[i](2-12)(2-14)(4-12)(4-14)(2-15)(4-15)(5-12)(5-14)(5-15)(2-13)(4-13)(3-12)(3-14)(3-13)(3-15)(5-13)(0-10)<2><5><4><3><12><15><14><13>(0-11)(1-10)(1-11)<0><1><10><11>[f]");
 }
 
 TEST(two_1a)
@@ -963,7 +975,7 @@ TEST(two_1a)
   db::box_convert<db::SimplePolygon> bc2;
   bs.set_scanner_threshold (0);
   bs.process (tr, 1, bc1, bc2);
-  EXPECT_EQ (tr.str, "(2-11)(2-12)(1-11)(1-12)<1><2><11><12>(0-10)<0><10>");
+  EXPECT_EQ (tr.str, "[i](2-11)(2-12)(1-11)(1-12)<1><2><11><12>(0-10)<0><10>[f]");
 }
 
 TEST(two_1b)
@@ -999,12 +1011,12 @@ TEST(two_1b)
   db::box_convert<db::SimplePolygon> bc2;
   bs.set_scanner_threshold (0);
   EXPECT_EQ (bs.process (tr, 1, bc1, bc2), true);
-  EXPECT_EQ (tr.str, "(1-12)(2-12)(1-11)(2-11)<1><2><11><12>(0-10)<0><10>");
+  EXPECT_EQ (tr.str, "[i](1-12)(2-12)(1-11)(2-11)<1><2><11><12>(0-10)<0><10>[f]");
 
 
   BoxScannerTestRecorderTwoStopping trstop;
   EXPECT_EQ (bs.process (trstop, 1, bc1, bc2), false);
-  EXPECT_EQ (trstop.str, "(1-12)");
+  EXPECT_EQ (trstop.str, "[i](1-12)[f-]");
 }
 
 TEST(two_1c)
@@ -1035,7 +1047,7 @@ TEST(two_1c)
   db::box_convert<db::SimplePolygon> bc2;
   bs.set_scanner_threshold (0);
   EXPECT_EQ (bs.process (tr, 1, bc1, bc2), true);
-  EXPECT_EQ (tr.str, "<0><10>(1-12)(2-12)(1-11)(2-11)<1><2><12><11>");
+  EXPECT_EQ (tr.str, "[i]<0><10>(1-12)(2-12)(1-11)(2-11)<1><2><12><11>[f]");
 }
 
 void run_test2_two (tl::TestBase *_this, size_t n, double ff, db::Coord spread, bool touch = true)
diff --git a/src/db/unit_tests/dbDeepEdgesTests.cc b/src/db/unit_tests/dbDeepEdgesTests.cc
index 2fa7f90d2..33ff2c563 100644
--- a/src/db/unit_tests/dbDeepEdgesTests.cc
+++ b/src/db/unit_tests/dbDeepEdgesTests.cc
@@ -131,6 +131,7 @@ TEST(3_Edge2EdgeBooleans)
   db::Region r3 (db::RecursiveShapeIterator (ly, top_cell, l3), dss);
   db::Region r2and3 = r2 & r3;
 
+  db::Edges e2 = r2.edges ();
   db::Edges e3 = r3.edges ();
   db::Edges e2and3 = r2and3.edges ();
 
@@ -144,6 +145,8 @@ TEST(3_Edge2EdgeBooleans)
   target.insert (target_top_cell_index, target.get_layer (db::LayerProperties (20, 0)), e3 & e2and3);
   target.insert (target_top_cell_index, target.get_layer (db::LayerProperties (21, 0)), e3 - e2and3);
   target.insert (target_top_cell_index, target.get_layer (db::LayerProperties (22, 0)), e3 ^ e2and3);
+  target.insert (target_top_cell_index, target.get_layer (db::LayerProperties (23, 0)), e3.intersections(e2and3));
+  target.insert (target_top_cell_index, target.get_layer (db::LayerProperties (24, 0)), e3.intersections(e2));
 
   CHECKPOINT();
   db::compare_layouts (_this, target, tl::testsrc () + "/testdata/algo/deep_edges_au3.gds");
diff --git a/src/db/unit_tests/dbEdges.cc b/src/db/unit_tests/dbEdges.cc
index ace673825..eff26ff66 100644
--- a/src/db/unit_tests/dbEdges.cc
+++ b/src/db/unit_tests/dbEdges.cc
@@ -852,9 +852,37 @@ TEST(22)
   ee.insert (db::Edge (4000,-2000,-2000,-2000));
 
   EXPECT_EQ ((e & ee).to_string (), "(400,0;-2000,0);(500,-174;400,0);(1000,0;900,-173);(4000,0;1000,0)");
-  EXPECT_EQ (e.intersections (ee).to_string (), "(400,0;400,0);(-2000,0;-2000,0);(1000,0;1000,0);(4000,0;4000,0);(400,0;-2000,0);(500,-174;400,0);(1000,0;900,-173);(4000,0;1000,0)");
-  //  no particular new points with intersections - just endpoints of original edges
-  EXPECT_EQ (e.intersections (ee).merged ().to_string (), "(400,0;-2000,0);(500,-174;400,0);(1000,0;900,-173);(4000,0;1000,0)");
+  EXPECT_EQ (e.intersections (ee).to_string (), "(400,0;-2000,0);(500,-174;400,0);(1000,0;900,-173);(4000,0;1000,0)");
+
+  //  Edge/edge intersections
+  ee.clear ();
+  e.clear ();
+  e.insert (db::Edge (0, -100, 0, 150));
+  ee.insert (db::Edge (-50, 50, 50, 50));
+  ee.insert (db::Edge (-50, 100, 50, 100));
+  EXPECT_EQ ((e & ee).to_string (), "");  //  AND does not report intersection points
+  EXPECT_EQ (e.intersections (ee).to_string (), "(0,50;0,50);(0,100;0,100)");
+
+  //  Edge is intersected by pair with connection point on this line
+  ee.clear ();
+  e.clear ();
+  e.insert (db::Edge (0, -100, 0, 150));
+  ee.insert (db::Edge (-50, 50, 0, 50));
+  ee.insert (db::Edge (0, 60, 50, 60));
+  ee.insert (db::Edge (-50, 100, 0, 100));
+  ee.insert (db::Edge (0, 100, 50, 100));
+  EXPECT_EQ ((e & ee).to_string (), "");  //  AND does not report intersection points
+  EXPECT_EQ (e.intersections (ee).to_string (), "(0,50;0,50);(0,60;0,60);(0,100;0,100)");
+
+  //  Coincident edges are crossed by another one
+  ee.clear ();
+  e.clear ();
+  e.insert (db::Edge (0, -100, 0, 250));
+  ee.insert (db::Edge (0, 0, 0, 150));
+  ee.insert (db::Edge (-50, 100, 50, 100));
+  ee.insert (db::Edge (-50, 200, 50, 200));
+  EXPECT_EQ ((e & ee).to_string (), "(0,0;0,150)");
+  EXPECT_EQ (e.intersections (ee).to_string (), "(0,0;0,150);(0,200;0,200)");
 }
 
 TEST(23)
diff --git a/testdata/algo/deep_edges_au3.gds b/testdata/algo/deep_edges_au3.gds
index ae59b5807..62914f828 100644
Binary files a/testdata/algo/deep_edges_au3.gds and b/testdata/algo/deep_edges_au3.gds differ
diff --git a/testdata/drc/drcSuiteTests.drc b/testdata/drc/drcSuiteTests.drc
index b3164b5cd..be4c43ed6 100644
--- a/testdata/drc/drcSuiteTests.drc
+++ b/testdata/drc/drcSuiteTests.drc
@@ -589,6 +589,22 @@ def run_testsuite(dm, ic, tiled = false, hier = false)
   p = c.edges.pull_interacting(b.edges)
   p.output(lb + 5, dm)
   
+  lb += 10 #440
+  message "--- edge booleans, intersections #{lb}"
+  
+  p = c.edges - b.edges
+  p.output(lb, dm)
+  p = b.edges - c.edges
+  p.output(lb + 1, dm)
+  p = c.edges & b.edges
+  p.output(lb + 2, dm)
+  p = c.edges ^ b.edges
+  p.output(lb + 3, dm)
+  p = c.edges.intersections(b.edges)
+  p.output(lb + 4, dm)
+  p = b.edges.intersections(c.edges)
+  p.output(lb + 5, dm)
+  
 end
 
 if $drc_test_mode == 1