diff --git a/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/OrientedFace.java b/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/OrientedFace.java
index 947f609..b4a5df0 100644
--- a/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/OrientedFace.java
+++ b/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/OrientedFace.java
@@ -34,6 +34,12 @@
 
 public abstract class OrientedFace implements Iterable<Vertex> {
 
+    private volatile V adjacentVertexOrdinal;
+
+    void clear() {
+        adjacentVertexOrdinal = null;
+    }
+
     /**
      * Perform a flip for deletion of the vertex from the tetrahedralization. The incident and adjacent tetrahedra form
      * an ear of the star set of tetrahedra adjacent to v.
@@ -287,23 +293,25 @@ public Tetrahedron[] flip3to2(int reflexEdge) {
      * @return
      */
     public Vertex getAdjacentVertex() {
-        if (getAdjacentVertexOrdinal() == null) {
+        var current = getAdjacentVertexOrdinal();
+        if (current == null) {
             return null;
         }
-        return getAdjacent().getVertex(getAdjacentVertexOrdinal());
+        return getAdjacent().getVertex(current);
     }
 
-    /**
-     * The vertex in the adjacent tetrahedron opposite of this face
-     */
     /**
      * Answer the canonical ordinal of the vertex in the adjacent tetrahedron which is opposite of this face.
      *
      * @return
      */
     public V getAdjacentVertexOrdinal() {
-        Tetrahedron adjacent = getAdjacent();
-        return adjacent == null ? null : adjacent.ordinalOf(getIncident());
+        var current = adjacentVertexOrdinal;
+        if (current == null) {
+            Tetrahedron adjacent = getAdjacent();
+            current = adjacentVertexOrdinal = adjacent == null ? null : adjacent.ordinalOf(getIncident());
+        }
+        return current;
     }
 
     /**
diff --git a/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/Tetrahedron.java b/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/Tetrahedron.java
index abab242..7c7ea2e 100644
--- a/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/Tetrahedron.java
+++ b/lucien/src/main/java/com/hellblazer/luciferase/lucien/grid/Tetrahedron.java
@@ -551,6 +551,7 @@ boolean isDeleted() {
      * @return
      */
     V ordinalOf(Tetrahedron neighbor) {
+        clear();
         if (nA == neighbor) {
             return A;
         }
@@ -569,6 +570,13 @@ V ordinalOf(Tetrahedron neighbor) {
         throw new IllegalArgumentException("Not a neighbor: " + neighbor);
     }
 
+    private void clear() {
+        faceADB.clear();
+        faceBCA.clear();
+        faceCBD.clear();
+        faceDAC.clear();
+    }
+
     /**
      * Patch the new tetrahedron created by a flip of the receiver by seting the neighbor to the value in the receiver
      * <p>
@@ -633,6 +641,7 @@ void removeAnyDegenerateTetrahedronPair() {
     }
 
     void setNeighbor(V v, Tetrahedron n) {
+        clear();
         if (v == A) {
             nA = n;
             return;
@@ -645,25 +654,26 @@ void setNeighbor(V v, Tetrahedron n) {
             nC = n;
             return;
         }
-        if (v == D) {
-            nD = n;
-            return;
-        }
+        nD = n;
     }
 
     void setNeighborA(Tetrahedron t) {
+        clear();
         nA = t;
     }
 
     void setNeighborB(Tetrahedron t) {
+        clear();
         nB = t;
     }
 
     void setNeighborC(Tetrahedron t) {
+        clear();
         nC = t;
     }
 
     void setNeighborD(Tetrahedron t) {
+        clear();
         nD = t;
     }