diff --git a/agents.py b/agents.py
index a5bf376ca..742cd6c40 100644
--- a/agents.py
+++ b/agents.py
@@ -35,7 +35,7 @@
 #
 # Speed control in GUI does not have any effect -- fix it.
 
-from grid import distance2, turn_heading
+from grid import distance_squared, turn_heading
 from statistics import mean
 
 import random
@@ -397,8 +397,8 @@ def things_near(self, location, radius=None):
         if radius is None:
             radius = self.perceptible_distance
         radius2 = radius * radius
-        return [(thing, radius2 - distance2(location, thing.location)) for thing in self.things
-                if distance2(location, thing.location) <= radius2]
+        return [(thing, radius2 - distance_squared(location, thing.location)) for thing in self.things
+                if distance_squared(location, thing.location) <= radius2]
 
     def percept(self, agent):
         """By default, agent perceives things within a default radius."""
diff --git a/grid.py b/grid.py
index 4400d217b..a7e032136 100644
--- a/grid.py
+++ b/grid.py
@@ -26,8 +26,8 @@ def distance(a, b):
     return math.hypot((a[0] - b[0]), (a[1] - b[1]))
 
 
-def distance2(a, b):
-    "The square of the distance between two (x, y) points."
+def distance_squared(a, b):
+    """The square of the distance between two (x, y) points."""
     return (a[0] - b[0])**2 + (a[1] - b[1])**2
 
 
diff --git a/tests/test_grid.py b/tests/test_grid.py
index 5e05a617a..928218150 100644
--- a/tests/test_grid.py
+++ b/tests/test_grid.py
@@ -10,8 +10,8 @@ def test_distance():
     assert distance((1, 2), (5, 5)) == 5.0
 
 
-def test_distance2():
-    assert distance2((1, 2), (5, 5)) == 25.0
+def test_distance_squared():
+    assert distance_squared((1, 2), (5, 5)) == 25.0
 
 
 def test_vector_clip():