diff --git a/experiment.t b/experiment.t
index d1378bf..3b547cc 100644
--- a/experiment.t
+++ b/experiment.t
@@ -42,5 +42,6 @@ gameMain: GameMainDef
 ;
 
 #include "src/room/orangeRoom.t"
+#include "src/room/yellowRoom.t"
 
 #include "src/actor/pc.t"
diff --git a/src/room/orangeRoom.t b/src/room/orangeRoom.t
index 5254221..1c1da74 100644
--- a/src/room/orangeRoom.t
+++ b/src/room/orangeRoom.t
@@ -12,8 +12,20 @@ orangeRoom: DarkRoom
     The room contains
     an ascetic bed
     and a desk against the east wall."
+  south = orangeDoor
 ;
 
+/* Doors */
+
++ orangeDoor:
+  Door
+  'white sliding door'
+  'sliding door'
+  "White sliding door in south wall.<br>"
+  isListed = true;
+
+/* Lights */
+
 + OnOffControl, Fixture
   'small luminous switch/light/lights'
   'small luminous switch'
@@ -29,6 +41,7 @@ orangeRoom: DarkRoom
   makeOn (val) {
     inherited(val);
     location.brightness = val ? 3 : 0;
+    isListed = val ? nil : true;
 
     val
       ? "You hear slight hum of neon lamps, followed with bright light."
@@ -42,6 +55,8 @@ orangeRoom: DarkRoom
   "Ordinary neon lamps emit cold light."
 ;
 
+/* Content */
+
 + Decoration
   'orange digits/number'
   'orange number'
diff --git a/src/room/yellowRoom.t b/src/room/yellowRoom.t
new file mode 100644
index 0000000..f5d726f
--- /dev/null
+++ b/src/room/yellowRoom.t
@@ -0,0 +1,16 @@
+yellowRoom: Room
+  'Yellow room'
+  " This is another room which every surface
+    covered with matte white panels.
+    <.p>
+    There is a door in the north direction."
+  north = orangeDoorOutside
+;
+
+/* Doors */
+
++ orangeDoorOutside: Door -> orangeDoor
+  'sliding door'
+  'door number <<gameMain.experimentNumber>>'
+  "Door number <<gameMain.experimentNumber>>.<br>"
+;