--- a/src/proto2/Physics.cc	Tue Nov 18 18:21:32 2008 +0000
+++ b/src/proto2/Physics.cc	Tue Nov 18 18:29:05 2008 +0000
@@ -10,7 +10,11 @@
 }
 
 void PhysicsWorld::tick () {
-    std::for_each(objects.begin(), objects.end(), /*TODO: tick*/);
+    std::for_each(objects.begin(), objects.end(), tickObject);
+}
+
+void tickObject(PhysicsObject* obj) {
+    obj->tick();
 }
 
 PhysicsObject::PhysicsObject (mass, position, velocity, force) 

--- a/src/proto2/Physics.hh	Tue Nov 18 18:21:32 2008 +0000
+++ b/src/proto2/Physics.hh	Tue Nov 18 18:29:05 2008 +0000
@@ -43,4 +43,6 @@
         void tick (void);
 };
 
+void tickObject(PhysicsObject* obj);
+
 #endif