diff --git a/main/HalfEdge.pde b/main/HalfEdge.pde
index 9c5a463..a077589 100644
--- a/main/HalfEdge.pde
+++ b/main/HalfEdge.pde
@@ -28,6 +28,7 @@ public class HalfEdge {
     if (try1 == null) {
        twin.setnext(this);
        previous = twin;
+       v1.setIncidentEdge(this);
     } else {
        twin.setnext(try1[1]);
        previous = try1[0];
@@ -37,6 +38,7 @@ public class HalfEdge {
     if (try2 == null) {
        twin.setprevious(this);
        next = twin;
+       v2.setIncidentEdge(twin);
     } else {
        twin.setprevious(try2[0]);
        next = try2[1];