diff --git a/src/primitive.rs b/src/primitive.rs
index 58e1827..c662497 100644
--- a/src/primitive.rs
+++ b/src/primitive.rs
@@ -50,6 +50,10 @@ pub trait GetOtherEnd<F: GetNodeIndex, T: GetNodeIndex + Into<F>>: GetEnds<F, T>
     }
 }
 
+pub trait GetWraparound: GetLayout + GetNodeIndex {
+    fn wraparound(&self) -> Option<LooseBendIndex>;
+}
+
 pub trait GetFirstRail: GetLayout + GetNodeIndex {
     fn first_rail(&self) -> Option<LooseBendIndex> {
         self.layout()
@@ -287,6 +291,12 @@ impl<'a> MakeShape for FixedDot<'a> {
 
 impl<'a> GetFirstRail for FixedDot<'a> {}
 
+impl<'a> GetWraparound for FixedDot<'a> {
+    fn wraparound(&self) -> Option<LooseBendIndex> {
+        self.first_rail()
+    }
+}
+
 pub type LooseDot<'a> = GenericPrimitive<'a, LooseDotWeight>;
 impl_loose_primitive!(LooseDot, LooseDotWeight);
 
@@ -467,6 +477,11 @@ impl<'a> GetEnds<FixedDotIndex, FixedDotIndex> for FixedBend<'a> {
 
 impl<'a> GetOtherEnd<FixedDotIndex, FixedDotIndex> for FixedBend<'a> {}
 impl<'a> GetFirstRail for FixedBend<'a> {}
+impl<'a> GetWraparound for FixedBend<'a> {
+    fn wraparound(&self) -> Option<LooseBendIndex> {
+        self.first_rail()
+    }
+}
 impl<'a> GetCore for FixedBend<'a> {} // TODO: Fixed bends don't have cores actually.
                                       //impl<'a> GetInnerOuter for FixedBend<'a> {}
 
@@ -537,5 +552,10 @@ impl<'a> GetEnds<LooseDotIndex, LooseDotIndex> for LooseBend<'a> {
 }
 
 impl<'a> GetOtherEnd<LooseDotIndex, LooseDotIndex> for LooseBend<'a> {}
+impl<'a> GetWraparound for LooseBend<'a> {
+    fn wraparound(&self) -> Option<LooseBendIndex> {
+        self.outer()
+    }
+}
 impl<'a> GetCore for LooseBend<'a> {}
 impl<'a> GetInnerOuter for LooseBend<'a> {}