diff --git a/src/db/db/dbTriangle.cc b/src/db/db/dbTriangle.cc
index 26dbc4789..9f4f49fa3 100644
--- a/src/db/db/dbTriangle.cc
+++ b/src/db/db/dbTriangle.cc
@@ -68,8 +68,8 @@ Vertex::Vertex (db::DCoord x, db::DCoord y)
 bool
 Vertex::is_outside () const
 {
-  for (auto e = m_edges.begin (); e != m_edges.end (); ++e) {
-    if (e->is_outside ()) {
+  for (auto e = mp_edges.begin (); e != mp_edges.end (); ++e) {
+    if ((*e)->is_outside ()) {
       return true;
     }
   }
@@ -81,8 +81,8 @@ Vertex::triangles () const
 {
   std::set<db::Triangle *> seen;
   std::vector<db::Triangle *> res;
-  for (auto e = m_edges.begin (); e != m_edges.end (); ++e) {
-    for (auto t = e->begin_triangles (); t != e->end_triangles (); ++t) {
+  for (auto e = mp_edges.begin (); e != mp_edges.end (); ++e) {
+    for (auto t = (*e)->begin_triangles (); t != (*e)->end_triangles (); ++t) {
       if (seen.insert (t.operator-> ()).second) {
         res.push_back (t.operator-> ());
       }
@@ -94,8 +94,8 @@ Vertex::triangles () const
 bool
 Vertex::has_edge (const TriangleEdge *edge) const
 {
-  for (auto e = m_edges.begin (); e != m_edges.end (); ++e) {
-    if (e.operator-> () == edge) {
+  for (auto e = mp_edges.begin (); e != mp_edges.end (); ++e) {
+    if (*e == edge) {
       return true;
     }
   }
@@ -107,11 +107,23 @@ Vertex::to_string (bool with_id) const
 {
   std::string res = tl::sprintf ("(%.12g, %.12g)", x (), y());
   if (with_id) {
-    res += tl::sprintf ("[%p]", (void *)this);
+    res += tl::sprintf ("[%x]", (size_t)this);
   }
   return res;
 }
 
+void
+Vertex::remove_edge (db::TriangleEdge *edge)
+{
+  for (auto e = mp_edges.begin (); e != mp_edges.end (); ++e) {
+    if (*e == edge) {
+      mp_edges.erase (e);
+      return;
+    }
+  }
+  tl_assert (false);
+}
+
 int
 Vertex::in_circle (const DPoint &point, const DPoint &center, double radius)
 {
@@ -141,8 +153,7 @@ TriangleEdge::TriangleEdge ()
 TriangleEdge::TriangleEdge (Vertex *v1, Vertex *v2)
   : mp_v1 (v1), mp_v2 (v2), mp_left (), mp_right (), m_level (0), m_id (0), m_is_segment (false)
 {
-  v1->m_edges.push_back (this);
-  v2->m_edges.push_back (this);
+  //  .. nothing yet ..
 }
 
 void
@@ -157,14 +168,33 @@ TriangleEdge::set_right (Triangle *t)
   mp_right = t;
 }
 
+void
+TriangleEdge::link ()
+{
+  mp_v1->mp_edges.push_back (this);
+  mp_v2->mp_edges.push_back (this);
+}
+
+void
+TriangleEdge::unlink ()
+{
+  if (mp_v1) {
+    mp_v1->remove_edge (this);
+  }
+  if (mp_v2) {
+    mp_v2->remove_edge (this);
+  }
+  mp_v1 = mp_v2 = 0;
+}
+
 Triangle *
 TriangleEdge::other (const Triangle *t) const
 {
-  if (t == mp_left.get ()) {
-    return const_cast<Triangle *> (mp_right.get ());
+  if (t == mp_left) {
+    return mp_right;
   }
-  if (t == mp_right.get ()) {
-    return const_cast<Triangle *> (mp_left.get ());
+  if (t == mp_right) {
+    return mp_left;
   }
   tl_assert (false);
   return 0;
@@ -206,7 +236,7 @@ TriangleEdge::to_string (bool with_id) const
 {
   std::string res = std::string ("(") + mp_v1->to_string (with_id) + ", " + mp_v2->to_string (with_id) + ")";
   if (with_id) {
-    res += tl::sprintf ("[%p]", (void *)this);
+    res += tl::sprintf ("[%x]", (size_t)this);
   }
   return res;
 }
@@ -341,6 +371,11 @@ Triangle::Triangle (TriangleEdge *e1, TriangleEdge *e2, TriangleEdge *e3)
   }
 }
 
+Triangle::~Triangle ()
+{
+  unlink ();
+}
+
 void
 Triangle::unlink ()
 {
@@ -376,7 +411,6 @@ Triangle::to_string (bool with_id) const
 Vertex *
 Triangle::vertex (int n) const
 {
-  tl_assert (mp_e1 && mp_e2 && mp_e3);
   n = (n + 3) % 3;
   if (n == 0) {
     return mp_v1;
@@ -392,11 +426,11 @@ Triangle::edge (int n) const
 {
   n = (n + 3) % 3;
   if (n == 0) {
-    return const_cast<TriangleEdge *> (mp_e1.get ());
+    return mp_e1;
   } else if (n == 1) {
-    return const_cast<TriangleEdge *> (mp_e2.get ());
+    return mp_e2;
   } else {
-    return const_cast<TriangleEdge *> (mp_e3.get ());
+    return mp_e3;
   }
 }
 
diff --git a/src/db/db/dbTriangle.h b/src/db/db/dbTriangle.h
index ae050b19a..4d5bc4931 100644
--- a/src/db/db/dbTriangle.h
+++ b/src/db/db/dbTriangle.h
@@ -48,7 +48,7 @@ class DB_PUBLIC Vertex
   : public db::DPoint
 {
 public:
-  typedef tl::weak_collection<db::TriangleEdge> edges_type;
+  typedef std::vector<TriangleEdge *> edges_type;
   typedef edges_type::const_iterator edges_iterator;
 
   Vertex ();
@@ -61,9 +61,9 @@ public:
   bool is_outside () const;
   std::vector<db::Triangle *> triangles () const;
 
-  edges_iterator begin_edges () const { return m_edges.begin (); }
-  edges_iterator end_edges () const { return m_edges.end (); }
-  size_t num_edges () const { return m_edges.size (); }
+  edges_iterator begin_edges () const { return mp_edges.begin (); }
+  edges_iterator end_edges () const { return mp_edges.end (); }
+  size_t num_edges () const { return mp_edges.size (); }
 
   bool has_edge (const TriangleEdge *edge) const;
 
@@ -88,8 +88,9 @@ public:
 
 private:
   friend class TriangleEdge;
+  void remove_edge (db::TriangleEdge *edge);
 
-  edges_type m_edges;
+  edges_type mp_edges;
   size_t m_level;
 };
 
@@ -97,7 +98,6 @@ private:
  *  @brief A class representing an edge in the Delaunay triangulation graph
  */
 class DB_PUBLIC TriangleEdge
-  : public tl::Object
 {
 public:
   class TriangleIterator
@@ -153,7 +153,6 @@ public:
   };
 
   TriangleEdge ();
-  TriangleEdge (Vertex *v1, Vertex *v2);
 
   Vertex *v1 () const { return mp_v1; }
   Vertex *v2 () const { return mp_v2; }
@@ -162,14 +161,14 @@ public:
   {
     std::swap (mp_v1, mp_v2);
 
-    Triangle *l = mp_left.get ();
-    Triangle *r = mp_right.get ();
+    Triangle *l = mp_left;
+    Triangle *r = mp_right;
     mp_left = r;
     mp_right = l;
   }
 
-  Triangle *left  () const { return const_cast<Triangle *> (mp_left.get ()); }
-  Triangle *right () const { return const_cast<Triangle *> (mp_right.get ()); }
+  Triangle *left  () const { return mp_left; }
+  Triangle *right () const { return mp_right; }
 
   TriangleIterator begin_triangles () const
   {
@@ -385,19 +384,23 @@ public:
    */
   bool has_triangle (const Triangle *t) const;
 
+  //  --- exposed for test purposes only ---
+
+  TriangleEdge (Vertex *v1, Vertex *v2);
+
+  void unlink ();
+  void link ();
+
 private:
   friend class Triangle;
+  friend class Triangles;
 
   Vertex *mp_v1, *mp_v2;
-  tl::weak_ptr<Triangle> mp_left, mp_right;
+  Triangle *mp_left, *mp_right;
   size_t m_level;
   size_t m_id;
   bool m_is_segment;
 
-  //  no copying
-  // @@@ TriangleEdge &operator= (const TriangleEdge &);
-  // @@@ TriangleEdge (const TriangleEdge &);
-
   void set_left  (Triangle *t);
   void set_right (Triangle *t);
 };
@@ -425,6 +428,8 @@ public:
   Triangle ();
   Triangle (TriangleEdge *e1, TriangleEdge *e2, TriangleEdge *e3);
 
+  ~Triangle ();
+
   void unlink ();
 
   void set_id (size_t id) { m_id = id; }
@@ -499,7 +504,7 @@ public:
    */
   bool has_edge (const db::TriangleEdge *e) const
   {
-    return mp_e1.get () == e || mp_e2.get () == e || mp_e3.get () == e;
+    return mp_e1 == e || mp_e2 == e || mp_e3 == e;
   }
 
   /**
@@ -524,7 +529,7 @@ public:
 
 private:
   bool m_is_outside;
-  tl::weak_ptr<TriangleEdge> mp_e1, mp_e2, mp_e3;
+  TriangleEdge *mp_e1, *mp_e2, *mp_e3;
   db::Vertex *mp_v1, *mp_v2, *mp_v3;
   size_t m_id;
 
diff --git a/src/db/db/dbTriangles.cc b/src/db/db/dbTriangles.cc
index 419600709..6a6c9c373 100644
--- a/src/db/db/dbTriangles.cc
+++ b/src/db/db/dbTriangles.cc
@@ -44,8 +44,6 @@ Triangles::~Triangles ()
   while (! mp_triangles.empty ()) {
     remove (mp_triangles.front ());
   }
-
-  tl_assert (mp_edges.empty ());
 }
 
 db::Vertex *
@@ -65,10 +63,10 @@ Triangles::create_vertex (const db::DPoint &pt)
 db::TriangleEdge *
 Triangles::create_edge (db::Vertex *v1, db::Vertex *v2)
 {
-  db::TriangleEdge *res = new db::TriangleEdge (v1, v2);
-  res->set_id (++m_id);
-  mp_edges.push_back (res);
-  return res;
+  m_edges_heap.push_back (db::TriangleEdge (v1, v2));
+  m_edges_heap.back ().link ();
+  m_edges_heap.back ().set_id (++m_id);
+  return &m_edges_heap.back ();
 }
 
 db::Triangle *
@@ -93,7 +91,7 @@ Triangles::remove (db::Triangle *tri)
   //  clean up edges we do no longer need
   for (int i = 0; i < 3; ++i) {
     if (edges [i] && edges [i]->left () == 0 && edges [i]->right () == 0) {
-      delete edges [i];
+      edges [i]->unlink ();
     }
   }
 }
@@ -172,7 +170,11 @@ Triangles::check (bool check_delaunay) const
     }
   }
 
-  for (auto e = mp_edges.begin (); e != mp_edges.end (); ++e) {
+  for (auto e = m_edges_heap.begin (); e != m_edges_heap.end (); ++e) {
+
+    if (!e->left () && !e->right ()) {
+      continue;
+    }
 
     if (e->left () && e->right ()) {
       if (e->left ()->is_outside () != e->right ()->is_outside () && ! e->is_segment ()) {
@@ -181,11 +183,6 @@ Triangles::check (bool check_delaunay) const
       }
     }
 
-    if (!e->left () && !e->right ()) {
-      tl::error << "(check error) found orphan edge " << e->to_string (true);
-      res = false;
-    }
-
     for (auto t = e->begin_triangles (); t != e->end_triangles (); ++t) {
       if (! t->has_edge (e.operator-> ())) {
         tl::error << "(check error) edge " << e->to_string (true) << " not found in adjacent triangle " << t->to_string (true);
@@ -223,7 +220,7 @@ Triangles::check (bool check_delaunay) const
   for (auto v = m_vertex_heap.begin (); v != m_vertex_heap.end (); ++v) {
     unsigned int num_outside_edges = 0;
     for (auto e = v->begin_edges (); e != v->end_edges (); ++e) {
-      if (e->is_outside ()) {
+      if ((*e)->is_outside ()) {
         ++num_outside_edges;
       }
     }
@@ -231,8 +228,8 @@ Triangles::check (bool check_delaunay) const
       tl::error << "(check error) vertex " << v->to_string (true) << " has " << num_outside_edges << " outside edges (can only be 2)";
       res = false;
       for (auto e = v->begin_edges (); e != v->end_edges (); ++e) {
-        if (e->is_outside ()) {
-          tl::error << "  Outside edge is " << e->to_string (true);
+        if ((*e)->is_outside ()) {
+          tl::error << "  Outside edge is " << (*e)->to_string (true);
         }
       }
     }
@@ -264,8 +261,8 @@ Triangles::to_layout () const
     top.shapes (t->is_outside () ? l2 : l1).insert (dbu_trans * poly);
   }
 
-  for (auto e = mp_edges.begin (); e != mp_edges.end (); ++e) {
-    if (e->is_segment ()) {
+  for (auto e = m_edges_heap.begin (); e != m_edges_heap.end (); ++e) {
+    if ((e->left () || e->right ()) && e->is_segment ()) {
       top.shapes (l10).insert (dbu_trans * e->edge ());
     }
   }
@@ -301,7 +298,7 @@ Triangles::find_points_around (db::Vertex *vertex, double radius)
     next_vertexes.clear ();
     for (auto v = new_vertexes.begin (); v != new_vertexes.end (); ++v) {
       for (auto e = (*v)->begin_edges (); e != (*v)->end_edges (); ++e) {
-        db::Vertex *ov = e->other (*v);
+        db::Vertex *ov = (*e)->other (*v);
         if (ov->in_circle (*vertex, radius) == 1 && seen.insert (ov).second) {
           next_vertexes.push_back (ov);
           res.push_back (ov);
@@ -386,7 +383,7 @@ Triangles::find_closest_edge (const db::DPoint &p, db::Vertex *vstart, bool insi
 {
   if (!vstart) {
 
-    if (! mp_edges.empty ()) {
+    if (! mp_triangles.empty ()) {
 
       unsigned int ls = 0;
       size_t n = m_vertex_heap.size ();
@@ -395,13 +392,14 @@ Triangles::find_closest_edge (const db::DPoint &p, db::Vertex *vstart, bool insi
       //  A sample heuristics that takes a sqrt(N) sample from the
       //  vertexes to find a good starting point
 
-      vstart = mp_edges.front ()->v1 ();
+      vstart = mp_triangles.front ()->vertex (0);
       double dmin = vstart->distance (p);
 
       while (ls * ls < m) {
         m /= 2;
         for (size_t i = m / 2; i < n; i += m) {
           ++ls;
+          //  NOTE: this assumes the heap is not too loaded with orphan vertexes
           db::Vertex *v = (m_vertex_heap.begin () + i).operator-> ();
           if (v->begin_edges () != v->end_edges ()) {
             double d = v->distance (p);
@@ -435,20 +433,20 @@ Triangles::find_closest_edge (const db::DPoint &p, db::Vertex *vstart, bool insi
       if (inside_only) {
         //  NOTE: in inside mode we stay on the line of sight as we don't
         //  want to walk around outside pockets.
-        if (! e->is_segment () && e->is_for_outside_triangles ()) {
+        if (! (*e)->is_segment () && (*e)->is_for_outside_triangles ()) {
           continue;
         }
-        if (! e->crosses_including (line)) {
+        if (! (*e)->crosses_including (line)) {
           continue;
         }
       }
 
-      double ds = e->distance (p);
+      double ds = (*e)->distance (p);
 
       if (d < 0.0 || ds < d) {
 
         d = ds;
-        edge = const_cast<db::TriangleEdge *> (e.operator-> ());
+        edge = *e;
         vnext = edge->other (v);
 
       } else if (fabs (ds - d) < std::max (1.0, fabs (ds) + fabs (d)) * db::epsilon) {
@@ -456,15 +454,15 @@ Triangles::find_closest_edge (const db::DPoint &p, db::Vertex *vstart, bool insi
         //  this differentiation selects the edge which bends further towards
         //  the target point if both edges share a common point and that
         //  is the one the determines the distance.
-        db::Vertex *cv = edge->common_vertex (e.operator-> ());
+        db::Vertex *cv = edge->common_vertex (*e);
         if (cv) {
           db::DVector edge_d = *edge->other (cv) - *cv;
-          db::DVector e_d = *e->other(cv) - *cv;
+          db::DVector e_d = *(*e)->other(cv) - *cv;
           db::DVector r = p - *cv;
           double edge_sp = db::sprod (r, edge_d) / edge_d.length ();
           double s_sp = db::sprod (r, e_d) / e_d.length ();
           if (s_sp > edge_sp) {
-            edge = const_cast<db::TriangleEdge *> (e.operator-> ());
+            edge = *e;
             vnext = edge->other (v);
           }
         }
@@ -550,10 +548,10 @@ Triangles::add_more_triangles (std::vector<db::Triangle *> &new_triangles,
     db::TriangleEdge *next_edge = 0;
 
     for (auto e = from_vertex->begin_edges (); e != from_vertex->end_edges (); ++e) {
-      if (! e->has_vertex (to_vertex) && e->is_outside ()) {
+      if (! (*e)->has_vertex (to_vertex) && (*e)->is_outside ()) {
         //  TODO: remove and break
         tl_assert (next_edge == 0);
-        next_edge = const_cast<db::TriangleEdge *> (e.operator-> ());
+        next_edge = *e;
       }
     }
 
@@ -730,8 +728,8 @@ Triangles::remove_inside_vertex (db::Vertex *vertex, std::list<tl::weak_ptr<db::
 
     db::TriangleEdge *to_flip = 0;
     for (auto e = vertex->begin_edges (); e != vertex->end_edges () && to_flip == 0; ++e) {
-      if (e->can_flip ()) {
-        to_flip = const_cast<db::TriangleEdge *> (e.operator-> ());
+      if ((*e)->can_flip ()) {
+        to_flip = *e;
       }
     }
     if (! to_flip) {
@@ -756,8 +754,8 @@ Triangles::remove_inside_vertex (db::Vertex *vertex, std::list<tl::weak_ptr<db::
     //  in this case choose the "join" strategy
     db::TriangleEdge *jseg = 0;
     for (auto e = vertex->begin_edges (); e != vertex->end_edges () && !jseg; ++e) {
-      if (e->can_join_via (vertex)) {
-        jseg = const_cast <db::TriangleEdge *> (e.operator-> ());
+      if ((*e)->can_join_via (vertex)) {
+        jseg = *e;
       }
     }
     tl_assert (jseg != 0);
@@ -769,8 +767,8 @@ Triangles::remove_inside_vertex (db::Vertex *vertex, std::list<tl::weak_ptr<db::
 
     db::TriangleEdge *jseg_opp = 0;
     for (auto e = vertex->begin_edges (); e != vertex->end_edges () && !jseg_opp; ++e) {
-      if (!e->has_triangle (jseg->left ()) && !e->has_triangle (jseg->right ())) {
-        jseg_opp = const_cast <db::TriangleEdge *> (e.operator-> ());
+      if (!(*e)->has_triangle (jseg->left ()) && !(*e)->has_triangle (jseg->right ())) {
+        jseg_opp = *e;
       }
     }
 
@@ -1084,7 +1082,7 @@ Triangles::search_edges_crossing (Vertex *from, Vertex *to)
   std::vector<db::TriangleEdge *> result;
 
   for (auto e = v->begin_edges (); e != v->end_edges () && ! next_edge; ++e) {
-    for (auto t = e->begin_triangles (); t != e->end_triangles (); ++t) {
+    for (auto t = (*e)->begin_triangles (); t != (*e)->end_triangles (); ++t) {
       db::TriangleEdge *os = t->opposite (v);
       if (os->has_vertex (vv)) {
         return result;
@@ -1152,8 +1150,8 @@ Triangles::find_edge_for_points (const db::DPoint &p1, const db::DPoint &p2)
     return 0;
   }
   for (auto e = v->begin_edges (); e != v->end_edges (); ++e) {
-    if (e->other (v)->equal (p2)) {
-      return const_cast <db::TriangleEdge *>(e.operator-> ());
+    if ((*e)->other (v)->equal (p2)) {
+      return *e;
     }
   }
   return 0;
@@ -1240,9 +1238,9 @@ Triangles::join_edges (std::vector<db::TriangleEdge *> &edges)
 
     std::vector<db::TriangleEdge *> join_edges;
     for (auto e = cp->begin_edges (); e != cp->end_edges (); ++e) {
-      if (e.operator-> () != s1 && e.operator-> () != s2) {
-        if (e->can_join_via (cp)) {
-          join_edges.push_back (const_cast<db::TriangleEdge *> (e.operator-> ()));
+      if (*e != s1 && *e != s2) {
+        if ((*e)->can_join_via (cp)) {
+          join_edges.push_back (*e);
         } else {
           join_edges.clear ();
           break;
@@ -1380,7 +1378,7 @@ Triangles::remove_outside_triangles ()
 void
 Triangles::clear ()
 {
-  mp_edges.clear ();
+  m_edges_heap.clear ();
   mp_triangles.clear ();
   m_vertex_heap.clear ();
   m_is_constrained = false;
@@ -1549,7 +1547,7 @@ Triangles::triangulate (const db::Region &region, const TriangulateParameters &p
           for (auto v = vertexes_in_diametral_circle.begin (); v != vertexes_in_diametral_circle.end (); ++v) {
             bool has_segment = false;
             for (auto e = (*v)->begin_edges (); e != (*v)->end_edges () && ! has_segment; ++e) {
-              has_segment = e->is_segment ();
+              has_segment = (*e)->is_segment ();
             }
             if (! has_segment) {
               to_delete.push_back (*v);
diff --git a/src/db/db/dbTriangles.h b/src/db/db/dbTriangles.h
index ec0c0b269..bb085fbd8 100644
--- a/src/db/db/dbTriangles.h
+++ b/src/db/db/dbTriangles.h
@@ -253,7 +253,7 @@ public:
 
 private:
   tl::shared_collection<db::Triangle> mp_triangles;
-  tl::weak_collection<db::TriangleEdge> mp_edges;
+  tl::stable_vector<db::TriangleEdge> m_edges_heap;
   tl::stable_vector<db::Vertex> m_vertex_heap;
   bool m_is_constrained;
   size_t m_level;
diff --git a/src/db/unit_tests/dbTriangleTests.cc b/src/db/unit_tests/dbTriangleTests.cc
index 0b326e9b7..263d9ca07 100644
--- a/src/db/unit_tests/dbTriangleTests.cc
+++ b/src/db/unit_tests/dbTriangleTests.cc
@@ -52,7 +52,7 @@ static std::string edges_from_vertex (const db::Vertex &v)
     if (! res.empty ()) {
       res += ", ";
     }
-    res += e->to_string ();
+    res += (*e)->to_string ();
   }
   return res;
 }
@@ -77,20 +77,24 @@ TEST(Vertex_edge_registration)
   db::Vertex v3 (2, 1);
 
   std::unique_ptr<db::TriangleEdge> e1 (new db::TriangleEdge (&v1, &v2));
+  e1->link ();
   EXPECT_EQ (edges_from_vertex (v1), "((0, 0), (1, 2))");
   EXPECT_EQ (edges_from_vertex (v2), "((0, 0), (1, 2))");
   EXPECT_EQ (edges_from_vertex (v3), "");
 
   std::unique_ptr<db::TriangleEdge> e2 (new db::TriangleEdge (&v2, &v3));
+  e2->link ();
   EXPECT_EQ (edges_from_vertex (v1), "((0, 0), (1, 2))");
   EXPECT_EQ (edges_from_vertex (v2), "((0, 0), (1, 2)), ((1, 2), (2, 1))");
   EXPECT_EQ (edges_from_vertex (v3), "((1, 2), (2, 1))");
 
+  e2->unlink ();
   e2.reset (0);
   EXPECT_EQ (edges_from_vertex (v1), "((0, 0), (1, 2))");
   EXPECT_EQ (edges_from_vertex (v2), "((0, 0), (1, 2))");
   EXPECT_EQ (edges_from_vertex (v3), "");
 
+  e1->unlink ();
   e1.reset (0);
   EXPECT_EQ (edges_from_vertex (v1), "");
   EXPECT_EQ (edges_from_vertex (v2), "");
@@ -106,8 +110,11 @@ TEST(Vertex_triangles)
   EXPECT_EQ (triangles_from_vertex (v1), "");
 
   std::unique_ptr<db::TriangleEdge> e1 (new db::TriangleEdge (&v1, &v2));
+  e1->link ();
   std::unique_ptr<db::TriangleEdge> e2 (new db::TriangleEdge (&v2, &v3));
+  e2->link ();
   std::unique_ptr<db::TriangleEdge> e3 (new db::TriangleEdge (&v3, &v1));
+  e3->link ();
 
   std::unique_ptr<db::Triangle> tri (new db::Triangle (e1.get (), e2.get (), e3.get ()));
   EXPECT_EQ (triangles_from_vertex (v1), "((0, 0), (1, 2), (2, 1))");
@@ -115,12 +122,20 @@ TEST(Vertex_triangles)
   EXPECT_EQ (triangles_from_vertex (v3), "((0, 0), (1, 2), (2, 1))");
 
   std::unique_ptr<db::TriangleEdge> e4 (new db::TriangleEdge (&v1, &v4));
+  e4->link ();
   std::unique_ptr<db::TriangleEdge> e5 (new db::TriangleEdge (&v2, &v4));
+  e5->link ();
   std::unique_ptr<db::Triangle> tri2 (new db::Triangle (e1.get (), e4.get (), e5.get ()));
   EXPECT_EQ (triangles_from_vertex (v1), "((0, 0), (-1, 2), (1, 2)), ((0, 0), (1, 2), (2, 1))");
   EXPECT_EQ (triangles_from_vertex (v2), "((0, 0), (-1, 2), (1, 2)), ((0, 0), (1, 2), (2, 1))");
   EXPECT_EQ (triangles_from_vertex (v3), "((0, 0), (1, 2), (2, 1))");
   EXPECT_EQ (triangles_from_vertex (v4), "((0, 0), (-1, 2), (1, 2))");
+
+  tri->unlink ();
+  EXPECT_EQ (triangles_from_vertex (v1), "((0, 0), (-1, 2), (1, 2))");
+
+  tri2->unlink ();
+  EXPECT_EQ (triangles_from_vertex (v1), "");
 }
 
 //  Tests for Triangle class
diff --git a/src/db/unit_tests/dbTrianglesTests.cc b/src/db/unit_tests/dbTrianglesTests.cc
index 412a12ce5..8c404f86f 100644
--- a/src/db/unit_tests/dbTrianglesTests.cc
+++ b/src/db/unit_tests/dbTrianglesTests.cc
@@ -643,8 +643,6 @@ TEST(create_constrained_delaunay)
 
 TEST(triangulate)
 {
-  tl::equals(1.0, 2.0);
-  return; // @@@
   db::Region r;
   r.insert (db::Box (0, 0, 10000, 10000));
 
@@ -669,7 +667,6 @@ TEST(triangulate)
 
   EXPECT_GT (tri.num_triangles (), size_t (100));
   EXPECT_LT (tri.num_triangles (), size_t (150));
-  tl::info << tri.num_triangles ();
 
   param.min_b = 1.0;
   param.max_area = 0.1;