diff --git a/dat/bigrm-12.lua b/dat/bigrm-12.lua
new file mode 100644
index 000000000..0e41bd9e4
--- /dev/null
+++ b/dat/bigrm-12.lua
@@ -0,0 +1,85 @@
+-- NetHack bigroom bigrm-12.lua	$NHDT-Date: $  $NHDT-Branch: NetHack-3.7 $
+--	Copyright (c) 2024 by Pasi Kallinen
+-- NetHack may be freely redistributed.  See license for details.
+--
+-- Two hexagons
+
+des.level_flags("mazelevel", "noflipy");
+des.level_init({ style = "solidfill", fg = " " });
+
+des.map([[
+                                                                           
+         .......................           .......................         
+        .........................         .........................        
+       ...........................       ...........................       
+      .............................     .............................      
+     ........PPPPPPPPPPPPPPP........   ........LLLLLLLLLLLLLLL........     
+    ........PPPPPPPPPPPPPPPPP........ ........LLLLLLLLLLLLLLLLL........    
+   ........PPPWWWWWWWWWWWWWPPP...............LLLZZZZZZZZZZZZZLLL........   
+  ........PPPWWWWWWWWWWWWWWWPPP.............LLLZZZZZZZZZZZZZZZLLL........  
+ ........PPPWWWWWWWWWWWWWWWWWPPP...........LLLZZZZZZZZZZZZZZZZZLLL........ 
+  ........PPPWWWWWWWWWWWWWWWPPP.............LLLZZZZZZZZZZZZZZZLLL........  
+   ........PPPWWWWWWWWWWWWWPPP...............LLLZZZZZZZZZZZZZLLL........   
+    ........PPPPPPPPPPPPPPPPP........ ........LLLLLLLLLLLLLLLLL........    
+     ........PPPPPPPPPPPPPPP........   ........LLLLLLLLLLLLLLL........     
+      .............................     .............................      
+       ...........................       ...........................       
+        .........................         .........................        
+         .......................           .......................         
+                                                                           
+]]);
+
+-- maybe replace lavawalls/waterwalls with stone walls
+if percent(20) then
+   if percent(50) then
+      des.replace_terrain({ fromterrain = "W", toterrain = "-" });
+   end
+   if percent(50) then
+      des.replace_terrain({ fromterrain = "Z", toterrain = "-" });
+   end
+end
+
+-- maybe replace pools with floor and then possibly walls with pools
+if percent(25) then
+   des.replace_terrain({ fromterrain = "P", toterrain = "." });
+   if percent(75) then
+      des.replace_terrain({ fromterrain = "W", toterrain = "P" });
+   end
+end
+if percent(25) then
+   des.replace_terrain({ fromterrain = "L", toterrain = "." });
+   if percent(75) then
+      des.replace_terrain({ fromterrain = "Z", toterrain = "L" });
+   end
+end
+
+-- maybe make both sides have the same terrain
+if percent(20) then
+   if percent(50) then
+      -- both are lava
+      des.replace_terrain({ fromterrain = "P", toterrain = "L" });
+      des.replace_terrain({ fromterrain = "W", toterrain = "Z" });
+   else
+      -- both are water
+      des.replace_terrain({ fromterrain = "L", toterrain = "P" });
+      des.replace_terrain({ fromterrain = "Z", toterrain = "W" });
+   end
+end
+
+des.region(selection.area(00,00,75,19), "lit")
+des.non_diggable();
+
+des.wallify();
+
+des.stair("up");
+des.stair("down");
+
+for i = 1,15 do
+   des.object();
+end
+for i = 1,6 do
+   des.trap();
+end
+for i = 1,28 do
+  des.monster();
+end
diff --git a/dat/dungeon.lua b/dat/dungeon.lua
index ff9e9130a..eb6223d66 100644
--- a/dat/dungeon.lua
+++ b/dat/dungeon.lua
@@ -70,7 +70,7 @@ dungeon = {
             base = 10,
             range = 3,
             chance = 40,
-            nlevels = 11
+            nlevels = 12
          },
          {
             name = "medusa",
diff --git a/sys/unix/NetHack.xcodeproj/project.pbxproj b/sys/unix/NetHack.xcodeproj/project.pbxproj
index 8e8caa1a5..55f36fd7f 100644
--- a/sys/unix/NetHack.xcodeproj/project.pbxproj
+++ b/sys/unix/NetHack.xcodeproj/project.pbxproj
@@ -1423,6 +1423,8 @@
 				"$(NH_DAT_DIR)/Bar-strt.lua",
 				"$(NH_DAT_DIR)/bigrm-1.lua",
 				"$(NH_DAT_DIR)/bigrm-10.lua",
+				"$(NH_DAT_DIR)/bigrm-11.lua",
+				"$(NH_DAT_DIR)/bigrm-12.lua",
 				"$(NH_DAT_DIR)/bigrm-2.lua",
 				"$(NH_DAT_DIR)/bigrm-3.lua",
 				"$(NH_DAT_DIR)/bigrm-4.lua",
diff --git a/sys/windows/GNUmakefile b/sys/windows/GNUmakefile
index 4e6ee45e5..29085431c 100644
--- a/sys/windows/GNUmakefile
+++ b/sys/windows/GNUmakefile
@@ -449,6 +449,7 @@ CLEAN_FILE += $(NHLUAH)
 LUALIST = air Arc-fila Arc-filb Arc-goal Arc-loca Arc-strt \
 	asmodeus astral baalz Bar-fila Bar-filb Bar-goal \
 	Bar-loca Bar-strt bigrm-1 bigrm-10 bigrm-11 bigrm-2 \
+	bigrm-12 \
 	bigrm-3 bigrm-4 bigrm-5 bigrm-6 bigrm-7 bigrm-8 \
 	bigrm-9 castle Cav-fila Cav-filb Cav-goal Cav-loca \
 	Cav-strt dungeon earth fakewiz1 fakewiz2 fire \
diff --git a/sys/windows/Makefile.nmake b/sys/windows/Makefile.nmake
index 5da031bec..7d72c27eb 100644
--- a/sys/windows/Makefile.nmake
+++ b/sys/windows/Makefile.nmake
@@ -554,6 +554,7 @@ LUA_FILES = $(DAT)\air.lua  $(DAT)\Arc-fila.lua $(DAT)\Arc-filb.lua \
 	$(DAT)\Bar-fila.lua $(DAT)\Bar-filb.lua $(DAT)\Bar-goal.lua \
 	$(DAT)\Bar-loca.lua $(DAT)\Bar-strt.lua $(DAT)\bigrm-1.lua \
 	$(DAT)\bigrm-10.lua $(DAT)\bigrm-11.lua $(DAT)\bigrm-2.lua \
+	$(DAT)\bigrm-12.lua \
 	$(DAT)\bigrm-3.lua  $(DAT)\bigrm-4.lua  $(DAT)\bigrm-5.lua \
 	$(DAT)\bigrm-6.lua  $(DAT)\bigrm-7.lua  $(DAT)\bigrm-8.lua \
 	$(DAT)\bigrm-9.lua  $(DAT)\castle.lua   $(DAT)\Cav-fila.lua \
diff --git a/sys/windows/vs/files.props b/sys/windows/vs/files.props
index 9dd50ca4c..16a62721e 100644
--- a/sys/windows/vs/files.props
+++ b/sys/windows/vs/files.props
@@ -32,6 +32,7 @@
     <Luafiles Include = "bigrm-1.lua"/>
     <Luafiles Include = "bigrm-10.lua"/>
     <Luafiles Include = "bigrm-11.lua"/>
+    <Luafiles Include = "bigrm-12.lua"/>
     <Luafiles Include = "bigrm-2.lua"/>
     <Luafiles Include = "bigrm-3.lua"/>
     <Luafiles Include = "bigrm-4.lua"/>