diff --git a/buildings/trailer-house.gd b/buildings/trailer-house.gd
index 17b486a..87ca97e 100644
--- a/buildings/trailer-house.gd
+++ b/buildings/trailer-house.gd
@@ -1,6 +1,6 @@
 extends Reference
 
-static func build_house(main_xform: Transform):
+static func build_house2(main_xform: Transform):
 	var rnd = streaming.get_place_rnd(main_xform)
 	print(main_xform.origin, " seed = ", rnd.state)
 	var l = 5 + 2 * (rnd.randi() % 5) - 1
@@ -52,3 +52,116 @@ static func build_house(main_xform: Transform):
 		objects.push_back({"xform": xform, "data": obj_data})
 	return objects
 
+static func build_walls(pos: Vector3, rnd: RandomNumberGenerator):
+	var objects = []
+	var xt = [Transform(Basis(), pos), Transform(Basis().rotated(Vector3.UP, PI), pos - Vector3(0, 0, 2))]
+	for x in range(xt.size()):
+		var obj_data = []
+		if rnd.randf() > 0.5:
+			obj_data.push_back("wall_solid")
+		elif rnd.randf() > 0.5:
+			obj_data.push_back("window_narrow")
+		else:
+			obj_data.push_back("window_wide")
+		objects.push_back({"xform": xt[x], "data": obj_data})
+	return objects
+
+static func build_house(main_xform: Transform):
+	var rnd = streaming.get_place_rnd(main_xform)
+	var terminals = [
+		"side_wall",
+		"side_wall_rotated",
+		"room",
+		"entry",
+		"room_range",
+		"wheels_room"
+	]
+	var grammar = {
+		"start": ["side_wall", "room", "wheels_room", "rooms_entry", "wheels_room", "side_wall_rotated"],
+		"rooms_entry": ["rooms", "entry!", "rooms"],
+		"rooms": ["rooms#", ["room", "range!"]],
+		"entry!": ["entry"],
+		"range!": ["room_range"],
+		"rooms#": ["rooms"]
+	}
+	var seen = {}
+	var queue = ["start"]
+	var complete = false
+	while !complete:
+		complete = true
+		var data = []
+		for k in range(queue.size()):
+			var item = queue[k]
+			print("item=", item)
+			if !item in terminals:
+				complete = false
+				for de in grammar[item]:
+					var e
+					if typeof(de) == TYPE_ARRAY:
+						while true:
+							e = de[rnd.randi() % de.size()]
+							if !e.ends_with("!") || !seen.has(e):
+								break
+					else:
+						e = de
+					print("e=", e)
+					if e.ends_with("!"):
+						if seen.has(e):
+							continue
+						else:
+							seen[e] = 1
+					if e.ends_with("#"):
+						if queue.size() < 12:
+							if rnd.randf() >= 0.3:
+								data.push_back(e)
+					else:
+						data.push_back(e)
+			else:
+				data.push_back(item)
+		queue = data
+		if complete:
+			if !seen.has("entry!") || !seen.has("range!"):
+				complete = false
+				seen.clear()
+				queue = ["start"]
+	print("queue: ", queue)
+	var objects = []
+	for k in range(queue.size()):
+		var pos = Vector3(0, 0, k * 2)
+		var xform = Transform(Basis(), pos)
+		var xt = [Transform(Basis(), pos), Transform(Basis().rotated(Vector3.UP, PI), pos - Vector3(0, 0, 2))]
+		match queue[k]:
+			"side_wall":
+				objects.push_back({"xform": xform, "data": ["side_wall", "bottom_side"]})
+			"room":
+				objects.push_back({"xform": xform, "data": ["roof_floor", "bottom"]})
+				objects.append_array(build_walls(pos, rnd))
+				if rnd.randf() > 0.6:
+					objects.push_back({"xform": xform, "data": ["wall_internal"]})
+			"wheels_room":
+				objects.push_back({"xform": xform, "data": ["roof_floor", "bottom_wheels"]})
+				objects.append_array(build_walls(pos, rnd))
+				if rnd.randf() > 0.6:
+					objects.push_back({"xform": xform, "data": ["wall_internal"]})
+			"room_range":
+				objects.push_back({"xform": xform, "data": ["roof_floor_range", "bottom"]})
+				objects.append_array(build_walls(pos, rnd))
+				if rnd.randf() > 0.6:
+					objects.push_back({"xform": xform, "data": ["wall_internal"]})
+			"entry":
+				for x in range(xt.size()):
+					var obj_data = []
+					if x == 0:
+						continue
+					if rnd.randf() > 0.5:
+						obj_data.push_back("wall_solid")
+					elif rnd.randf() > 0.5:
+						obj_data.push_back("window_narrow")
+					else:
+						obj_data.push_back("window_wide")
+					objects.push_back({"xform": xt[x], "data": obj_data})
+				objects.push_back({"xform": xform, "data": ["roof_floor", "entry", "bottom"]})
+			"side_wall_rotated":
+				objects.append_array(build_walls(pos, rnd))
+				objects.push_back({"xform": xform, "data": ["roof_floor", "side_wall_rotated", "bottom_side_rotated", "bottom"]})
+	return objects