diff --git a/src/autorouter/autoroute.rs b/src/autorouter/autoroute.rs
index f5285ef..34d168c 100644
--- a/src/autorouter/autoroute.rs
+++ b/src/autorouter/autoroute.rs
@@ -20,7 +20,7 @@ use crate::{
     router::{
         navcord::Navcord, navmesh::Navmesh, thetastar::ThetastarStepper, RouteStepper, Router,
     },
-    stepper::{Abort, EstimateProgress, Step},
+    stepper::{Abort, EstimateProgress, Permute, Step},
 };
 
 use super::{
@@ -87,22 +87,6 @@ impl AutorouteExecutionStepper {
         })
     }
 
-    fn permute(
-        &mut self,
-        autorouter: &mut Autorouter<impl AccessMesadata>,
-        permutation: Vec<RatlineIndex>,
-    ) -> Result<(), AutorouterError> {
-        let new_index = permutation
-            .iter()
-            .zip(self.ratlines.iter())
-            .position(|(permuted, original)| *permuted != *original)
-            .unwrap();
-        self.ratlines = permutation;
-
-        self.backtrace_to_index(autorouter, new_index)?;
-        Ok(())
-    }
-
     fn backtrace_to_index(
         &mut self,
         autorouter: &mut Autorouter<impl AccessMesadata>,
@@ -236,6 +220,27 @@ impl<M: AccessMesadata> Abort<Autorouter<M>> for AutorouteExecutionStepper {
     }
 }
 
+impl<M: AccessMesadata> Permute<Autorouter<M>> for AutorouteExecutionStepper {
+    type Index = RatlineIndex;
+    type Output = Result<(), AutorouterError>;
+
+    fn permute(
+        &mut self,
+        autorouter: &mut Autorouter<M>,
+        permutation: Vec<RatlineIndex>,
+    ) -> Result<(), AutorouterError> {
+        let new_index = permutation
+            .iter()
+            .zip(self.ratlines.iter())
+            .position(|(permuted, original)| *permuted != *original)
+            .unwrap();
+        self.ratlines = permutation;
+
+        self.backtrace_to_index(autorouter, new_index)?;
+        Ok(())
+    }
+}
+
 impl EstimateProgress for AutorouteExecutionStepper {
     type Value = f64;
 
diff --git a/src/stepper.rs b/src/stepper.rs
index 6f9dba7..86e6c3f 100644
--- a/src/stepper.rs
+++ b/src/stepper.rs
@@ -53,6 +53,14 @@ pub trait Abort<Ctx> {
     fn abort(&mut self, context: &mut Ctx);
 }
 
+/// Some steppers may be permuted from their initial order.
+pub trait Permute<Ctx> {
+    type Index;
+    type Output;
+
+    fn permute(&mut self, context: &mut Ctx, ordering: Vec<Self::Index>) -> Self::Output;
+}
+
 /// Steppers that can receive discrete events and act on them implement this
 /// trait.
 // XXX: Doesn't this violate the rule that stepper's future states are