diff -Prub nethack-3.4.3/include/rm.h nethack-3.4.3-darkroom/include/rm.h
--- nethack-3.4.3/include/rm.h	2003-12-08 01:39:13.000000000 +0200
+++ nethack-3.4.3-darkroom/include/rm.h	2003-12-31 00:28:32.000000000 +0200
@@ -124,93 +124,94 @@
 #define S_bars		17	/* KMH -- iron bars */
 #define S_tree		18	/* KMH */
 #define S_room		19
-#define S_corr		20
-#define S_litcorr	21
-#define S_upstair	22
-#define S_dnstair	23
-#define S_upladder	24
-#define S_dnladder	25
-#define S_altar		26
-#define S_grave		27
-#define S_throne	28
-#define S_sink		29
-#define S_fountain	30
-#define S_pool		31
-#define S_ice		32
-#define S_lava		33
-#define S_vodbridge	34
-#define S_hodbridge	35
-#define S_vcdbridge	36	/* closed drawbridge, vertical wall */
-#define S_hcdbridge	37	/* closed drawbridge, horizontal wall */
-#define S_air		38
-#define S_cloud		39
-#define S_water		40
+#define S_darkroom	20
+#define S_corr		21
+#define S_litcorr	22
+#define S_upstair	23
+#define S_dnstair	24
+#define S_upladder	25
+#define S_dnladder	26
+#define S_altar		27
+#define S_grave		28
+#define S_throne	29
+#define S_sink		30
+#define S_fountain	31
+#define S_pool		32
+#define S_ice		33
+#define S_lava		34
+#define S_vodbridge	35
+#define S_hodbridge	36
+#define S_vcdbridge	37	/* closed drawbridge, vertical wall */
+#define S_hcdbridge	38	/* closed drawbridge, horizontal wall */
+#define S_air		39
+#define S_cloud		40
+#define S_water		41
 
 /* end dungeon characters, begin traps */
 
-#define S_arrow_trap		41
-#define S_dart_trap		42
-#define S_falling_rock_trap	43
-#define S_squeaky_board		44
-#define S_bear_trap		45
-#define S_land_mine		46
-#define S_rolling_boulder_trap	47
-#define S_sleeping_gas_trap	48
-#define S_rust_trap		49
-#define S_fire_trap		50
-#define S_pit			51
-#define S_spiked_pit		52
-#define S_hole			53
-#define S_trap_door		54
-#define S_teleportation_trap	55
-#define S_level_teleporter	56
-#define S_magic_portal		57
-#define S_web			58
-#define S_statue_trap		59
-#define S_magic_trap		60
-#define S_anti_magic_trap	61
-#define S_polymorph_trap	62
+#define S_arrow_trap		42
+#define S_dart_trap		43
+#define S_falling_rock_trap	44
+#define S_squeaky_board		45
+#define S_bear_trap		46
+#define S_land_mine		47
+#define S_rolling_boulder_trap	48
+#define S_sleeping_gas_trap	49
+#define S_rust_trap		50
+#define S_fire_trap		51
+#define S_pit			52
+#define S_spiked_pit		53
+#define S_hole			54
+#define S_trap_door		55
+#define S_teleportation_trap	56
+#define S_level_teleporter	57
+#define S_magic_portal		58
+#define S_web			59
+#define S_statue_trap		60
+#define S_magic_trap		61
+#define S_anti_magic_trap	62
+#define S_polymorph_trap	63
 
 /* end traps, begin special effects */
 
-#define S_vbeam		63	/* The 4 zap beam symbols.  Do NOT separate. */
-#define S_hbeam		64	/* To change order or add, see function     */
-#define S_lslant	65	/* zapdir_to_glyph() in display.c.	    */
-#define S_rslant	66
-#define S_digbeam	67	/* dig beam symbol */
-#define S_flashbeam	68	/* camera flash symbol */
-#define S_boomleft	69	/* thrown boomerang, open left, e.g ')'    */
-#define S_boomright	70	/* thrown boomerand, open right, e.g. '('  */
-#define S_ss1		71	/* 4 magic shield glyphs */
-#define S_ss2		72
-#define S_ss3		73
-#define S_ss4		74
+#define S_vbeam		64	/* The 4 zap beam symbols.  Do NOT separate. */
+#define S_hbeam		65	/* To change order or add, see function     */
+#define S_lslant	66	/* zapdir_to_glyph() in display.c.	    */
+#define S_rslant	67
+#define S_digbeam	68	/* dig beam symbol */
+#define S_flashbeam	69	/* camera flash symbol */
+#define S_boomleft	70	/* thrown boomerang, open left, e.g ')'    */
+#define S_boomright	71	/* thrown boomerand, open right, e.g. '('  */
+#define S_ss1		72	/* 4 magic shield glyphs */
+#define S_ss2		73
+#define S_ss3		74
+#define S_ss4		75
 
 /* The 8 swallow symbols.  Do NOT separate.  To change order or add, see */
 /* the function swallow_to_glyph() in display.c.			 */
-#define S_sw_tl		75	/* swallow top left [1]			*/
-#define S_sw_tc		76	/* swallow top center [2]	Order:	*/
-#define S_sw_tr		77	/* swallow top right [3]		*/
-#define S_sw_ml		78	/* swallow middle left [4]	1 2 3	*/
-#define S_sw_mr		79	/* swallow middle right [6]	4 5 6	*/
-#define S_sw_bl		80	/* swallow bottom left [7]	7 8 9	*/
-#define S_sw_bc		81	/* swallow bottom center [8]		*/
-#define S_sw_br		82	/* swallow bottom right [9]		*/
-
-#define S_explode1	83	/* explosion top left			*/
-#define S_explode2	84	/* explosion top center			*/
-#define S_explode3	85	/* explosion top right		 Ex.	*/
-#define S_explode4	86	/* explosion middle left		*/
-#define S_explode5	87	/* explosion middle center	 /-\	*/
-#define S_explode6	88	/* explosion middle right	 |@|	*/
-#define S_explode7	89	/* explosion bottom left	 \-/	*/
-#define S_explode8	90	/* explosion bottom center		*/
-#define S_explode9	91	/* explosion bottom right		*/
+#define S_sw_tl		76	/* swallow top left [1]			*/
+#define S_sw_tc		77	/* swallow top center [2]	Order:	*/
+#define S_sw_tr		78	/* swallow top right [3]		*/
+#define S_sw_ml		79	/* swallow middle left [4]	1 2 3	*/
+#define S_sw_mr		80	/* swallow middle right [6]	4 5 6	*/
+#define S_sw_bl		81	/* swallow bottom left [7]	7 8 9	*/
+#define S_sw_bc		82	/* swallow bottom center [8]		*/
+#define S_sw_br		83	/* swallow bottom right [9]		*/
+
+#define S_explode1	84	/* explosion top left			*/
+#define S_explode2	85	/* explosion top center			*/
+#define S_explode3	86	/* explosion top right		 Ex.	*/
+#define S_explode4	87	/* explosion middle left		*/
+#define S_explode5	88	/* explosion middle center	 /-\	*/
+#define S_explode6	89	/* explosion middle right	 |@|	*/
+#define S_explode7	90	/* explosion bottom left	 \-/	*/
+#define S_explode8	91	/* explosion bottom center		*/
+#define S_explode9	92	/* explosion bottom right		*/
 
 /* end effects */
 
-#define MAXPCHARS	92	/* maximum number of mapped characters */
-#define MAXDCHARS	41	/* maximum of mapped dungeon characters */
+#define MAXPCHARS	93	/* maximum number of mapped characters */
+#define MAXDCHARS	42	/* maximum of mapped dungeon characters */
 #define MAXTCHARS	22	/* maximum of mapped trap characters */
 #define MAXECHARS	29	/* maximum of mapped effects characters */
 #define MAXEXPCHARS	9	/* number of explosion characters */
diff -Prub nethack-3.4.3/src/display.c nethack-3.4.3-darkroom/src/display.c
--- nethack-3.4.3/src/display.c	2003-12-08 01:39:13.000000000 +0200
+++ nethack-3.4.3-darkroom/src/display.c	2003-12-31 12:56:34.000000000 +0200
@@ -179,7 +179,7 @@
     if (!cansee(x,y) && !lev->waslit) {
 	/* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
 	if (lev->typ == ROOM && glyph == cmap_to_glyph(S_room))
-	    glyph = cmap_to_glyph(S_stone);
+	    glyph = cmap_to_glyph(S_darkroom);
 	else if (lev->typ == CORR && glyph == cmap_to_glyph(S_litcorr))
 	    glyph = cmap_to_glyph(S_corr);
     }
@@ -306,7 +306,7 @@
 	/* turn remembered dark room squares dark */
 	if (!lev->waslit && lev->glyph == cmap_to_glyph(S_room) &&
 							    lev->typ == ROOM)
-	    lev->glyph = cmap_to_glyph(S_stone);
+	    lev->glyph = cmap_to_glyph(S_darkroom);
     } else
 	levl[x][y].glyph = cmap_to_glyph(S_stone);	/* default val */
 }
@@ -560,15 +560,14 @@
 		if (lev->typ != ROOM && lev->seenv) {
 		    map_background(x, y, 1);
 		} else {
-		    lev->glyph = lev->waslit ? cmap_to_glyph(S_room) :
-					       cmap_to_glyph(S_stone);
+		    lev->glyph = (!lev->waslit) ? cmap_to_glyph(S_darkroom) : cmap_to_glyph(S_room);
 		    show_glyph(x,y,lev->glyph);
 		}
 	    } else if ((lev->glyph >= cmap_to_glyph(S_stone) &&
-			lev->glyph < cmap_to_glyph(S_room)) ||
+			lev->glyph < cmap_to_glyph(S_darkroom)) ||
 		       glyph_is_invisible(levl[x][y].glyph)) {
-		lev->glyph = lev->waslit ? cmap_to_glyph(S_room) :
-					   cmap_to_glyph(S_stone);
+		lev->glyph = (!cansee(x,y) && !lev->waslit) ? cmap_to_glyph(S_darkroom) :
+					   cmap_to_glyph(S_room);
 		show_glyph(x,y,lev->glyph);
 	    }
 	} else {
@@ -608,7 +607,7 @@
 	/* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
 	if (lev->typ == ROOM &&
 		    lev->glyph == cmap_to_glyph(S_room) && !lev->waslit)
-	    show_glyph(x,y, lev->glyph = cmap_to_glyph(S_stone));
+	    show_glyph(x,y, lev->glyph = cmap_to_glyph(S_darkroom));
 	else if (lev->typ == CORR &&
 		    lev->glyph == cmap_to_glyph(S_litcorr) && !lev->waslit)
 	    show_glyph(x,y, lev->glyph = cmap_to_glyph(S_corr));
@@ -756,7 +755,7 @@
 	    if (lev->glyph == cmap_to_glyph(S_litcorr) && lev->typ == CORR)
 		show_glyph(x, y, lev->glyph = cmap_to_glyph(S_corr));
 	    else if (lev->glyph == cmap_to_glyph(S_room) && lev->typ == ROOM)
-		show_glyph(x, y, lev->glyph = cmap_to_glyph(S_stone));
+		show_glyph(x, y, lev->glyph = cmap_to_glyph(S_darkroom));
 	    else
 		goto show_mem;
 	} else {
@@ -1397,7 +1396,9 @@
 	case STONE:
 	    idx = level.flags.arboreal ? S_tree : S_stone;
 	    break;
-	case ROOM:		idx = S_room;	  break;
+	case ROOM:
+	    idx = (!cansee(x,y) && !ptr->waslit) ? S_darkroom : S_room;
+	    break;
 	case CORR:
 	    idx = (ptr->waslit || flags.lit_corridor) ? S_litcorr : S_corr;
 	    break;
@@ -1454,11 +1455,11 @@
 	    case DB_MOAT:  idx = S_pool; break;
 	    case DB_LAVA:  idx = S_lava; break;
 	    case DB_ICE:   idx = S_ice;  break;
-	    case DB_FLOOR: idx = S_room; break;
+	    case DB_FLOOR: idx = (!cansee(x,y) && !ptr->waslit) ? S_darkroom : S_room; break;
 	    default:
 		impossible("Strange db-under: %d",
 			   ptr->drawbridgemask & DB_UNDER);
-		idx = S_room; /* something is better than nothing */
+		idx = (!cansee(x,y) && !ptr->waslit) ? S_darkroom : S_room; /* something is better than nothing */
 		break;
 	    }
 	    break;
@@ -1467,7 +1468,7 @@
 	    break;
 	default:
 	    impossible("back_to_glyph:  unknown level type [ = %d ]",ptr->typ);
-	    idx = S_room;
+	    idx = (!cansee(x,y) && !ptr->waslit) ? S_darkroom : S_room;
 	    break;
     }
 
diff -Prub nethack-3.4.3/src/drawing.c nethack-3.4.3-darkroom/src/drawing.c
--- nethack-3.4.3/src/drawing.c	2003-12-08 01:39:13.000000000 +0200
+++ nethack-3.4.3-darkroom/src/drawing.c	2003-12-31 13:13:59.000000000 +0200
@@ -204,7 +204,7 @@
  *  Note:  {ibm|dec|mac}_graphics[] arrays also depend on this symbol order.
  */
 const struct symdef defsyms[MAXPCHARS] = {
-/* 0*/	{' ', "dark part of a room",C(NO_COLOR)},	/* stone */
+/* 0*/	{' ', "unexplored area",C(NO_COLOR)},	/* stone */
 	{'|', "wall",		C(CLR_GRAY)},	/* vwall */
 	{'-', "wall",		C(CLR_GRAY)},	/* hwall */
 	{'-', "wall",		C(CLR_GRAY)},	/* tlcorn */
@@ -224,6 +224,7 @@
 	{'#', "iron bars",	C(HI_METAL)},	/* bars */
 	{'#', "tree",		C(CLR_GREEN)},	/* tree */
 	{'.', "floor of a room",C(CLR_GRAY)},	/* room */
+	{'.', "dark part of a room",C(CLR_BLACK)},	/* dark room */
 /*20*/	{'#', "corridor",	C(CLR_GRAY)},	/* dark corr */
 	{'#', "lit corridor",	C(CLR_GRAY)},	/* lit corr (see mapglyph.c) */
 	{'<', "staircase up",	C(CLR_GRAY)},	/* upstair */
@@ -335,6 +336,7 @@
 	240,	/* S_bars:	equivalence symbol */
 	241,	/* S_tree:	plus or minus symbol */
 	0xfa,	/* S_room:	meta-z, centered dot */
+	g_FILLER(S_stone),	/* S_darkroom:	meta-z, centered dot */
 /*20*/	0xb0,	/* S_corr:	meta-0, light shading */
 	0xb1,	/* S_litcorr:	meta-1, medium shading */
 	g_FILLER(S_upstair),
@@ -434,6 +436,7 @@
 	0xfb,	/* S_bars:	meta-{, small pi */
 	0xe7,	/* S_tree:	meta-g, plus-or-minus */
 	0xfe,	/* S_room:	meta-~, centered dot */
+	g_FILLER(S_stone),	/* S_darkroom:	meta-~, centered dot */
 /*20*/	g_FILLER(S_corr),
 	g_FILLER(S_litcorr),
 	g_FILLER(S_upstair),
@@ -531,6 +534,7 @@
 	0xf0,	/* S_bars:	equivalency symbol */
 	0xf1,	/* S_tree:	plus-or-minus */
 	g_FILLER(S_Room),
+	g_FILLER(S_stone), /* S_darkroom */
 /*20*/	0xB0,	/* S_corr */
 	g_FILLER(S_litcorr),
 	g_FILLER(S_upstair),
diff -Prub nethack-3.4.3/src/mapglyph.c nethack-3.4.3-darkroom/src/mapglyph.c
--- nethack-3.4.3/src/mapglyph.c	2003-12-08 01:39:13.000000000 +0200
+++ nethack-3.4.3-darkroom/src/mapglyph.c	2003-12-31 00:28:32.000000000 +0200
@@ -116,7 +116,7 @@
 		color = CLR_MAGENTA;
 	    else if (offset == S_corr || offset == S_litcorr)
 		color = CLR_GRAY;
-	    else if (offset >= S_room && offset <= S_water)
+	    else if (offset >= S_room && offset <= S_water && offset != S_darkroom)
 		color = CLR_GREEN;
 	    else
 		color = NO_COLOR;
diff -Prub nethack-3.4.3/src/options.c nethack-3.4.3-darkroom/src/options.c
--- nethack-3.4.3/src/options.c	2003-12-08 01:39:13.000000000 +0200
+++ nethack-3.4.3-darkroom/src/options.c	2003-12-31 13:31:48.000000000 +0200
@@ -603,6 +603,11 @@
 	/* result in the player's preferred fruit [better than "\033"].	*/
 	obj_descr[SLIME_MOLD].oc_name = "fruit";
 
+        if (flags.lit_corridor && iflags.use_color) {
+            showsyms[S_darkroom]=showsyms[S_room];
+        } else {
+            showsyms[S_darkroom]=showsyms[S_stone];
+        }
 	return;
 }
 
@@ -2220,6 +2225,7 @@
 			     */
 			    vision_recalc(2);		/* shut down vision */
 			    vision_full_recalc = 1;	/* delayed recalc */
+			    if (iflags.use_color) need_redraw = TRUE;  /* darkroom refresh */
 			}
 			else if ((boolopt[i].addr) == &iflags.use_inverse ||
 					(boolopt[i].addr) == &iflags.showrace ||
@@ -2523,8 +2529,14 @@
 	}
 
 	destroy_nhwindow(tmpwin);
-	if (need_redraw)
+	if (need_redraw) {
+	    if (flags.lit_corridor && iflags.use_color) {
+		showsyms[S_darkroom]=showsyms[S_room];
+	    } else {
+		showsyms[S_darkroom]=showsyms[S_stone];
+	    }
 	    (void) doredraw();
+	}
 	return 0;
 }
 
diff -Prub nethack-3.4.3/src/pager.c nethack-3.4.3-darkroom/src/pager.c
--- nethack-3.4.3/src/pager.c	2003-12-08 01:39:13.000000000 +0200
+++ nethack-3.4.3-darkroom/src/pager.c	2003-12-31 13:20:02.000000000 +0200
@@ -261,7 +261,7 @@
 	int tnum = what_trap(glyph_to_trap(glyph));
 	Strcpy(buf, defsyms[trap_to_defsym(tnum)].explanation);
     } else if(!glyph_is_cmap(glyph)) {
-	Strcpy(buf,"dark part of a room");
+	Strcpy(buf,"unexplored area");
     } else switch(glyph_to_cmap(glyph)) {
     case S_altar:
 	if(!In_endgame(&u.uz))
@@ -631,8 +631,8 @@
 	for (hit_trap = FALSE, i = 0; i < MAXPCHARS; i++) {
 	    x_str = defsyms[i].explanation;
 	    if (sym == (from_screen ? showsyms[i] : defsyms[i].sym) && *x_str) {
-		/* avoid "an air", "a water", or "a floor of a room" */
-		int article = (i == S_room) ? 2 :		/* 2=>"the" */
+		/* avoid "an air", "a water", "a floor of a room", "a dark part of a room" */
+		int article = ((i == S_room)||(i == S_darkroom)) ? 2 :		/* 2=>"the" */
 			      !(strcmp(x_str, "air") == 0 ||	/* 1=>"an"  */
 				strcmp(x_str, "water") == 0);	/* 0=>(none)*/
 
diff -Prub nethack-3.4.3/win/share/other.txt nethack-3.4.3-darkroom/win/share/other.txt
--- nethack-3.4.3/win/share/other.txt	2003-12-08 01:39:14.000000000 +0200
+++ nethack-3.4.3-darkroom/win/share/other.txt	2003-12-31 00:28:33.000000000 +0200
@@ -14,7 +14,7 @@
 N = (255, 255, 255)
 O = (218, 218, 182)
 P = (108, 145, 182)
-# tile 0 (dark part of a room)
+# tile 0 (unexplored area)
 {
   AAAAAAAAAAAAAAAA
   AAAAAAAAAAAAAAAA
@@ -394,6 +394,25 @@
   MMMMMMMMMMMMMMMM
   MMMMMMMMMMMMMMMM
 }
+# tile 20 (dark part of a room)
+{
+  MAMAMAMAMAMAMAMA
+  AMAMAMAMAMAMAMAM
+  MAMAMAMAMAMAMAMA
+  AMAMAMAMAMAMAMAM
+  MAMAMAMAMAMAMAMA
+  AMAMAMAMAMAMAMAM
+  MAMAMAMAMAMAMAMA
+  AMAMAMAPPMAMAMAM
+  MAMAMAMPPAMAMAMA
+  AMAMAMAMAMAMAMAM
+  MAMAMAMAMAMAMAMA
+  AMAMAMAMAMAMAMAM
+  MAMAMAMAMAMAMAMA
+  AMAMAMAMAMAMAMAM
+  MAMAMAMAMAMAMAMA
+  AMAMAMAMAMAMAMAM
+}
 # tile 20 (corridor)
 {
   MMMMMMMMMMMMMMMM