diff --git a/main/CompGeo.pde b/main/CompGeo.pde
index f843bb2..1663b85 100644
--- a/main/CompGeo.pde
+++ b/main/CompGeo.pde
@@ -28,7 +28,7 @@ public static class CompGeo {
     if ((CCW(a,b,c) != CCW(a,b,d)) && ((CCW(c,d,a) != CCW(c,d,b)))) {
       return 1;
     }
-    if ((CCW(a,b,c) == 0) & (CCW(a,b,d) == 0)) {
+    if ((CCW(a,b,c) == 0) && (CCW(a,b,d) == 0)) {
       if (between(a,c,b) || between(a,d,b) || between(c,a,d) || between(c,b,d)) {
          return 1; 
       }
@@ -158,4 +158,4 @@ public static class CompGeo {
     } 
     return null;
   }
-}
\ No newline at end of file
+}
diff --git a/main/HalfEdge.pde b/main/HalfEdge.pde
index f75cf79..073cd34 100644
--- a/main/HalfEdge.pde
+++ b/main/HalfEdge.pde
@@ -269,10 +269,15 @@ public class HalfEdge {
   }
   
   private boolean intersectsEventually(Point p, Point q) {
-    if (this.getOrigin().equals(p)) { return false; }
-    if (this.getOrigin().equals(q)) { return false; }
-    if (CompGeo.intersect(p, q, this.getOrigin(), this.gettwin().getOrigin()) == 1) {
-       return true; 
+    boolean shared = false;
+    if (this.getOrigin().equals(p)) { shared = true; }
+    if (this.getOrigin().equals(q)) { shared = true; }
+    if (this.gettwin().getOrigin().equals(p)) { shared = true; }
+    if (this.gettwin().getOrigin().equals(q)) { shared  = true; }
+    if (shared == false) {
+      if (CompGeo.intersect(p, q, this.getOrigin(), this.gettwin().getOrigin()) == 1) {
+        return true; 
+      }
     }
     if (counted == false) {
        counted = true;
diff --git a/main/main.pde b/main/main.pde
index 0be5e5d..6705e98 100644
--- a/main/main.pde
+++ b/main/main.pde
@@ -133,7 +133,9 @@ public void insertMode(float x, float y) {
           if(p.getY() - 10 < pointclicked.getY() && p.getY() + 10 > pointclicked.getY()
             && p.getX() - 10 < pointclicked.getX() && p.getX() + 10 > pointclicked.getX()) { }
           else  {
+            if (!list.intersectsSomething(p, pointclicked)) { 
               HalfEdge h = new HalfEdge(p, pointclicked);
+            }
           }
         }
       }