diff --git a/nav.py b/nav.py
index 44d15f6..4fe895e 100644
--- a/nav.py
+++ b/nav.py
@@ -79,8 +79,9 @@ def distance(a, b):
 
 
 def legs(route):
-    """Return the legs (pairs of consecutive waypoints) of a route."""
-    return [(route[i], route[i + 1]) for i in range(len(route) - 1)]
+    """Yield the legs (pairs of consecutive waypoints) of a route."""
+    for i in range(1, len(route) - 1):
+        yield route[i], route[i + 1]
 
 
 def plan(destination):