You can no longer stack multiple windows of the same dir on a tile

code/game/objects/structures/windoor_assembly.dm

@@ -16,7 +16,7 @@
 	icon_state = "l_windoor_assembly01"
 	anchored = 0
 	density = 0
-	setDir(NORTH)
+	dir = NORTH
 
 	var/ini_dir
 	var/obj/item/weapon/electronics/airlock/electronics = null
@@ -32,8 +32,10 @@
 	..()
 	user << "<span class='notice'>Alt-click to rotate it clockwise.</span>"
 
-/obj/structure/windoor_assembly/New(dir=NORTH)
+/obj/structure/windoor_assembly/New(loc, set_dir)
 	..()
+	if(set_dir)
+		dir = set_dir
 	ini_dir = dir
 	air_update_turf(1)
 
@@ -45,6 +47,7 @@
 /obj/structure/windoor_assembly/Move()
 	var/turf/T = loc
 	..()
+	setDir(ini_dir)
 	move_update_air(T)
 
 /obj/structure/windoor_assembly/update_icon()
@@ -55,8 +58,17 @@
 		return 1
 	if(get_dir(loc, target) == dir) //Make sure looking at appropriate border
 		return !density
-	else
-		return 1
+	if(istype(mover, /obj/structure/window))
+		var/obj/structure/window/W = mover
+		if(!valid_window_location(loc, W.ini_dir))
+			return FALSE
+	else if(istype(mover, /obj/structure/windoor_assembly))
+		var/obj/structure/windoor_assembly/W = mover
+		if(!valid_window_location(loc, W.ini_dir))
+			return FALSE
+	else if(istype(mover, /obj/machinery/door/window) && !valid_window_location(loc, mover.dir))
+		return FALSE
+	return 1
 
 /obj/structure/windoor_assembly/CanAtmosPass(turf/T)
 	if(get_dir(loc, T) == dir)
@@ -313,20 +325,21 @@
 	set src in oview(1)
 	if(usr.stat || !usr.canmove || usr.restrained())
 		return
-	if (anchored)
+	if(anchored)
 		usr << "<span class='warning'>[src] cannot be rotated while it is fastened to the floor!</span>"
-		return 0
-	//if(state != "01")
-		//update_nearby_tiles(need_rebuild=1) //Compel updates before
+		return FALSE
 
-	setDir(turn(dir, 270))
+	var/target_dir = turn(dir, 270)
 
-	//if(state != "01")
-		//update_nearby_tiles(need_rebuild=1)
+	if(!valid_window_location(loc, target_dir))
+		usr << "<span class='warning'>[src] cannot be rotated in that direction!</span>"
+		return FALSE
+
+	setDir(target_dir)
 
 	ini_dir = dir
 	update_icon()
-	return
+	return TRUE
 
 /obj/structure/windoor_assembly/AltClick(mob/user)
 	..()

code/game/objects/structures/window.dm

@@ -55,7 +55,6 @@
 	if(rods)
 		debris += new /obj/item/stack/rods(src, rods)
 
-
 /obj/structure/window/narsie_act()
 	add_atom_colour(NARSIE_WINDOW_COLOUR, FIXED_COLOUR_PRIORITY)
 	for(var/obj/item/weapon/shard/shard in debris)
@@ -85,9 +84,17 @@
 		return 0	//full tile window, you can't move into it!
 	if(get_dir(loc, target) == dir)
 		return !density
-	else
-		return 1
-
+	if(istype(mover, /obj/structure/window))
+		var/obj/structure/window/W = mover
+		if(!valid_window_location(loc, W.ini_dir))
+			return FALSE
+	else if(istype(mover, /obj/structure/windoor_assembly))
+		var/obj/structure/windoor_assembly/W = mover
+		if(!valid_window_location(loc, W.ini_dir))
+			return FALSE
+	else if(istype(mover, /obj/machinery/door/window) && !valid_window_location(loc, mover.dir))
+		return FALSE
+	return 1
 
 /obj/structure/window/CheckExit(atom/movable/O as mob|obj, target)
 	if(istype(O) && O.checkpass(PASSGLASS))
@@ -251,13 +258,19 @@
 
 	if(anchored)
 		usr << "<span class='warning'>[src] cannot be rotated while it is fastened to the floor!</span>"
-		return 0
+		return FALSE
 
-	setDir(turn(dir, 90))
+	var/target_dir = turn(dir, 90)
+
+	if(!valid_window_location(loc, target_dir))
+		usr << "<span class='warning'>[src] cannot be rotated in that direction!</span>"
+		return FALSE
+
+	setDir(target_dir)
 	air_update_turf(1)
 	ini_dir = dir
 	add_fingerprint(usr)
-	return
+	return TRUE
 
 
 /obj/structure/window/verb/revrotate()
@@ -270,13 +283,19 @@
 
 	if(anchored)
 		usr << "<span class='warning'>[src] cannot be rotated while it is fastened to the floor!</span>"
-		return 0
+		return FALSE
 
-	setDir(turn(dir, 270))
+	var/target_dir = turn(dir, 270)
+
+	if(!valid_window_location(loc, target_dir))
+		usr << "<span class='warning'>[src] cannot be rotated in that direction!</span>"
+		return FALSE
+
+	setDir(target_dir)
 	air_update_turf(1)
 	ini_dir = dir
 	add_fingerprint(usr)
-	return
+	return TRUE
 
 /obj/structure/window/AltClick(mob/user)
 	..()
@@ -348,6 +367,9 @@
 
 	return 1
 
+/obj/structure/window/unanchored
+	anchored = FALSE
+
 /obj/structure/window/reinforced
 	name = "reinforced window"
 	icon_state = "rwindow"
@@ -357,6 +379,9 @@
 	explosion_block = 1
 	glass_type = /obj/item/stack/sheet/rglass
 
+/obj/structure/window/reinforced/unanchored
+	anchored = FALSE
+
 /obj/structure/window/reinforced/tinted
 	name = "tinted window"
 	icon_state = "twindow"
@@ -379,6 +404,9 @@
 	canSmoothWith = list(/obj/structure/window/fulltile, /obj/structure/window/reinforced/fulltile, /obj/structure/window/reinforced/tinted/fulltile)
 	glass_amount = 2
 
+/obj/structure/window/fulltile/unanchored
+	anchored = FALSE
+
 /obj/structure/window/reinforced/fulltile
 	icon = 'icons/obj/smooth_structures/reinforced_window.dmi'
 	icon_state = "r_window"
@@ -390,6 +418,9 @@
 	level = 3
 	glass_amount = 2
 
+/obj/structure/window/reinforced/fulltile/unanchored
+	anchored = FALSE
+
 /obj/structure/window/reinforced/tinted/fulltile
 	icon = 'icons/obj/smooth_structures/tinted_window.dmi'
 	icon_state = "tinted_window"
@@ -455,6 +486,7 @@
 		if(direct)
 			var/obj/effect/E = PoolOrNew(/obj/effect/overlay/temp/ratvar/window/single, get_turf(src))
 			setDir(direct)
+			ini_dir = direct
 			E.setDir(direct)
 			made_glow = TRUE
 	else
@@ -488,6 +520,9 @@
 		animate(src, color = previouscolor, time = 8)
 		addtimer(CALLBACK(src, /atom/proc/update_atom_colour), 8)
 
+/obj/structure/window/reinforced/clockwork/unanchored
+	anchored = FALSE
+
 /obj/structure/window/reinforced/clockwork/fulltile
 	icon_state = "clockwork_window"
 	smooth = SMOOTH_TRUE
@@ -498,3 +533,6 @@
 	level = 3
 	glass_amount = 2
 	made_glow = TRUE
+
+/obj/structure/window/reinforced/clockwork/fulltile/unanchored
+	anchored = FALSE