diff --git a/surf/geometry.py b/surf/geometry.py
index 090e2b7..c780317 100644
--- a/surf/geometry.py
+++ b/surf/geometry.py
@@ -95,6 +95,8 @@ class Vertex(list):
         # for now just assume type(other) = Vertex... bad, I know
         return Vertex(self.x + other.x, self.y + other.y, self.z + other.z)
 
+    __iadd__ = __add__
+
     def __radd__(self, other):
         return other + self