diff --git a/luprex/core/cpp/world-difftab.cpp b/luprex/core/cpp/world-difftab.cpp
index 48d4dfb6..ac8a2efa 100644
--- a/luprex/core/cpp/world-difftab.cpp
+++ b/luprex/core/cpp/world-difftab.cpp
@@ -3,8 +3,15 @@
 // This file contains the code to compare the contents of tables.
 // The top level functions in this file are:
 //
-//  World::diff_lua_tables
+//  World::diff_numbered_tables
 //  World::diff_tangible_databases
+//  World::patch_numbered_tables
+//  World::patch_tangible_databases
+//
+// It also contains these unit testing support routines:
+//
+//  table.diffcompare
+//  table.diffapply
 //
 // This file also contains all the support code needed to implement
 // this stuff.
@@ -321,6 +328,7 @@ void World::diff_numbered_tables(lua_State *master, StreamBuffer *sb) {
         MLS.rawgeti(mtab, mntmap, id);
         if (MLS.istable(mtab)) {
             SLS.rawgeti(stab, sntmap, id);
+            assert(SLS.istable(stab));
             int tw = sb->total_writes();
             sb->write_int32(id);
             nmodified += 1;
@@ -367,6 +375,44 @@ void World::diff_tangible_databases(const IdVector &basis, lua_State *master, St
     sb->overwrite_int32(write_count_after, nmodified);
 }
 
+void World::patch_numbered_tables(StreamBuffer *sb) {
+    lua_State *L = state();
+    LuaVar tangibles, ntmap, tab;
+    LuaStack LS(L, tangibles, ntmap, tab);
+    LS.rawget(tangibles, LuaRegistry, "tangibles");
+    LS.rawget(ntmap, LuaRegistry, "ntmap");
+    assert(LS.istable(tangibles));
+    assert(LS.istable(ntmap));
+
+    int nmodified = sb->read_int32();
+    for (int i = 0; i < nmodified; i++) {
+        int index = sb->read_int32();
+        LS.rawgeti(tab, ntmap, index);
+        assert(LS.istable(tab));
+        patch_table(LS, tangibles, ntmap, tab, sb);
+    }
+    LS.result();
+}
+
+void World::patch_tangible_databases(StreamBuffer *sb) {
+    lua_State *L = state();
+    LuaVar tangibles, ntmap, tab;
+    LuaStack LS(L, tangibles, ntmap, tab);
+    LS.rawget(tangibles, LuaRegistry, "tangibles");
+    LS.rawget(ntmap, LuaRegistry, "ntmap");
+    assert(LS.istable(tangibles));
+    assert(LS.istable(ntmap));
+
+    int nmodified = sb->read_int32();
+    for (int i = 0; i < nmodified; i++) {
+        int64_t id = sb->read_int64();
+        LS.rawgeti(tab, tangibles, id);
+        assert(LS.istable(tab));
+        patch_table(LS, tangibles, ntmap, tab, sb);
+    }
+    LS.result();
+}
+
 LuaDefine(table_diffcompare, "c") {
     LuaArg mtnmap, mtab, mstnmap, mstab, stnmap, stab;
     LuaRet dbgstring;
diff --git a/luprex/core/cpp/world.cpp b/luprex/core/cpp/world.cpp
index b24cdf4d..983c7d8b 100644
--- a/luprex/core/cpp/world.cpp
+++ b/luprex/core/cpp/world.cpp
@@ -59,7 +59,7 @@ World::World(util::WorldType wt) {
 
     // Create the globaldb in the registry.
     LS.rawset(LuaRegistry, "globaldb", LuaNewTable);
-    
+
     // Initialize the SourceDB.  At this stage, the sourcedb is
     // empty, so it's just populating the lua builtins.
     source_db_.init(state());
@@ -1072,7 +1072,7 @@ static bool worlds_identical(const std::unique_ptr<World> &w1, const std::unique
     return sbw1.contents_equal(&sbw2);
 }
 
-LuaDefine(unittests_world, "c") {
+LuaDefine(unittests_worlddiffs, "c") {
     std::unique_ptr<World> m, ss, cs;
     StreamBuffer sb;
     int ncreate;
@@ -1188,4 +1188,4 @@ LuaDefine(unittests_world, "c") {
     LuaAssert(L, worlds_identical(ss, cs));
 
     return 0;
-}
\ No newline at end of file
+}
diff --git a/luprex/core/cpp/world.hpp b/luprex/core/cpp/world.hpp
index b4548315..92b684a3 100644
--- a/luprex/core/cpp/world.hpp
+++ b/luprex/core/cpp/world.hpp
@@ -285,18 +285,10 @@ private:
     static void diff_visible_animations(const TanVector &mvis, const TanVector &svis, StreamBuffer *sb); 
     void patch_visible_animations(StreamBuffer *sb);
 
-    // Compare the numbered general tables.
-    //
-    void diff_numbered_tables(lua_State *master, StreamBuffer *sb);
-
-    // Compare the tangible databases.
-    //
-    void diff_tangible_databases(const IdVector &basis, lua_State *master, StreamBuffer *sb);
-
 public:
     ///////////////////////////////////////////////////////////
     //
-    // Numbering and pairing of lua tables.
+    // world-pairtab: Numbering and pairing of lua tables.
     //
     // The following routines pair up tables in the synchronous
     // model with tables in the master model, by assigning matching
@@ -347,6 +339,29 @@ public:
     //
     void unnumber_lua_tables();
 
+public:
+    ///////////////////////////////////////////////////////////
+    //
+    // world-difftab: Nonrecursive table comparison
+    //
+    // These routines compare tables in the master lua to the corresponding
+    // tables in the synchronous lua.  This is a nonrecursive process, because
+    // the recursion has already been done during the table enumeration process.
+    //
+    ///////////////////////////////////////////////////////////
+
+    // Compare the numbered general tables.
+    //
+    void diff_numbered_tables(lua_State *master, StreamBuffer *sb);
+
+    // Compare the tangible databases.
+    //
+    void diff_tangible_databases(const IdVector &basis, lua_State *master, StreamBuffer *sb);
+
+    void patch_numbered_tables(StreamBuffer *sb);
+
+    void patch_tangible_databases(StreamBuffer *sb);
+
 private:
     // Type of model
     util::WorldType world_type_;