diff --git a/Physics/MovingParticles3.mch b/Physics/MovingParticles3.mch
index 780722bbac990228ed1f4876c6cc7f9d97c7c11f..7033c369c69df22901fabac98cd2b51a58a9427c 100644
--- a/Physics/MovingParticles3.mch
+++ b/Physics/MovingParticles3.mch
@@ -7,7 +7,7 @@ DEFINITIONS
   SPEED_MULTIPLIER == 1000000.0;
   GRAV_MULTIPLIER == 1000000000000.0;
   MAXMASS == 1.989e30;
-  
+  "SORT.def";
   gravitation == %i.(i:OBJ | sigma_vecs(
                               SQUASH(
                                %j.(j:OBJ & j/=i |
diff --git a/VisB-Examples.prob2project b/VisB-Examples.prob2project
index f3b60eab3ca881127d79008571f43b71e857309a..b8dd07e61464a2ca4c68c857f1273e706e29870a 100644
--- a/VisB-Examples.prob2project
+++ b/VisB-Examples.prob2project
@@ -98,13 +98,27 @@
       ],
       "modelcheckingItems": [],
       "visBVisualisation": "Physics/three_bodies.json"
+    },
+    {
+      "name": "MovingParticles4",
+      "description": "",
+      "location": "Physics/MovingParticles4.mch",
+      "lastUsedPreferenceName": "default",
+      "ltlFormulas": [],
+      "ltlPatterns": [],
+      "symbolicCheckingFormulas": [],
+      "symbolicAnimationFormulas": [],
+      "testCases": [],
+      "traces": [],
+      "modelcheckingItems": [],
+      "visBVisualisation": null
     }
   ],
   "preferences": [],
   "metadata": {
     "fileType": "Project",
     "formatVersion": 9,
-    "savedAt": "2020-11-11T11:29:33.443088Z",
+    "savedAt": "2020-11-12T16:09:03.372063Z",
     "creator": "User",
     "proB2KernelVersion": "4.0.0-SNAPSHOT",
     "proBCliVersion": null,