diff --git a/game_api.txt b/game_api.txt
index 1864cba4279b6e1b021b20d59f449887f2330a2c..d5d09e92d6af8b1cc4258dca1046ddc7e52ef833 100644
--- a/game_api.txt
+++ b/game_api.txt
@@ -592,6 +592,48 @@ Default constants
 
 `default.LIGHT_MAX`  The maximum light level (see [Node definition] light_source)
 
+
+GUI and formspecs
+-----------------
+
+`default.get_hotbar_bg(x, y)`
+
+ * Get the hotbar background as string, containing the formspec elements
+ * x: Horizontal position in the formspec
+ * y: Vertical position in the formspec
+
+`default.gui_bg`
+
+ * Background color formspec element
+
+`default.gui_bg_img`
+
+ * Image overlay formspec element for the background to use in formspecs
+
+`default.gui_slots`
+
+ * `listcolors` formspec element that is used to format the slots in formspecs
+
+`default.gui_survival_form`
+
+ * Entire formspec for the survival inventory
+
+`default.get_chest_formspec(pos)`
+
+ * Get the chest formspec using the defined GUI elements
+ * pos: Location of the node
+
+`default.get_furnace_active_formspec(fuel_percent, item_percent)`
+
+ * Get the active furnace formspec using the defined GUI elements
+ * fuel_percent: Percent of how much the fuel is used
+ * item_percent: Percent of how much the item is cooked
+
+`default.get_furnace_inactive_formspec()`
+
+ * Get the inactive furnace formspec using the defined GUI elements
+
+
 Player API
 ----------
 
diff --git a/mods/default/furnace.lua b/mods/default/furnace.lua
index 3c9081dd50c7c8524fe4f755ceb2924272e6488d..1643d427cb8573ffe3fcf6165b826cc1650544ad 100644
--- a/mods/default/furnace.lua
+++ b/mods/default/furnace.lua
@@ -3,9 +3,8 @@
 -- Formspecs
 --
 
-local function active_formspec(fuel_percent, item_percent)
-	local formspec =
-		"size[8,8.5]"..
+function default.get_furnace_active_formspec(fuel_percent, item_percent)
+	return "size[8,8.5]"..
 		default.gui_bg..
 		default.gui_bg_img..
 		default.gui_slots..
@@ -25,28 +24,28 @@ local function active_formspec(fuel_percent, item_percent)
 		"listring[context;fuel]"..
 		"listring[current_player;main]"..
 		default.get_hotbar_bg(0, 4.25)
-	return formspec
 end
 
-local inactive_formspec =
-	"size[8,8.5]"..
-	default.gui_bg..
-	default.gui_bg_img..
-	default.gui_slots..
-	"list[context;src;2.75,0.5;1,1;]"..
-	"list[context;fuel;2.75,2.5;1,1;]"..
-	"image[2.75,1.5;1,1;default_furnace_fire_bg.png]"..
-	"image[3.75,1.5;1,1;gui_furnace_arrow_bg.png^[transformR270]"..
-	"list[context;dst;4.75,0.96;2,2;]"..
-	"list[current_player;main;0,4.25;8,1;]"..
-	"list[current_player;main;0,5.5;8,3;8]"..
-	"listring[context;dst]"..
-	"listring[current_player;main]"..
-	"listring[context;src]"..
-	"listring[current_player;main]"..
-	"listring[context;fuel]"..
-	"listring[current_player;main]"..
-	default.get_hotbar_bg(0, 4.25)
+function default.get_furnace_inactive_formspec()
+	return "size[8,8.5]"..
+		default.gui_bg..
+		default.gui_bg_img..
+		default.gui_slots..
+		"list[context;src;2.75,0.5;1,1;]"..
+		"list[context;fuel;2.75,2.5;1,1;]"..
+		"image[2.75,1.5;1,1;default_furnace_fire_bg.png]"..
+		"image[3.75,1.5;1,1;gui_furnace_arrow_bg.png^[transformR270]"..
+		"list[context;dst;4.75,0.96;2,2;]"..
+		"list[current_player;main;0,4.25;8,1;]"..
+		"list[current_player;main;0,5.5;8,3;8]"..
+		"listring[context;dst]"..
+		"listring[current_player;main]"..
+		"listring[context;src]"..
+		"listring[current_player;main]"..
+		"listring[context;fuel]"..
+		"listring[current_player;main]"..
+		default.get_hotbar_bg(0, 4.25)
+end
 
 --
 -- Node callback functions that are the same for active and inactive furnace
@@ -190,7 +189,7 @@ local function furnace_node_timer(pos, elapsed)
 	--
 	-- Update formspec, infotext and node
 	--
-	local formspec = inactive_formspec
+	local formspec
 	local item_state
 	local item_percent = 0
 	if cookable then
@@ -216,7 +215,7 @@ local function furnace_node_timer(pos, elapsed)
 		active = "active "
 		local fuel_percent = math.floor(fuel_time / fuel_totaltime * 100)
 		fuel_state = fuel_percent .. "%"
-		formspec = active_formspec(fuel_percent, item_percent)
+		formspec = default.get_furnace_active_formspec(fuel_percent, item_percent)
 		swap_node(pos, "default:furnace_active")
 		-- make sure timer restarts automatically
 		result = true
@@ -224,12 +223,14 @@ local function furnace_node_timer(pos, elapsed)
 		if not fuellist[1]:is_empty() then
 			fuel_state = "0%"
 		end
+		formspec = default.get_furnace_inactive_formspec()
 		swap_node(pos, "default:furnace")
 		-- stop timer on the inactive furnace
 		minetest.get_node_timer(pos):stop()
 	end
 
-	local infotext = "Furnace " .. active .. "(Item: " .. item_state .. "; Fuel: " .. fuel_state .. ")"
+	local infotext = "Furnace " .. active .. "(Item: " .. item_state ..
+		"; Fuel: " .. fuel_state .. ")"
 
 	--
 	-- Set meta values
@@ -266,7 +267,7 @@ minetest.register_node("default:furnace", {
 
 	on_construct = function(pos)
 		local meta = minetest.get_meta(pos)
-		meta:set_string("formspec", inactive_formspec)
+		meta:set_string("formspec", default.get_furnace_inactive_formspec())
 		local inv = meta:get_inventory()
 		inv:set_size('src', 1)
 		inv:set_size('fuel', 1)
@@ -327,4 +328,3 @@ minetest.register_node("default:furnace_active", {
 	allow_metadata_inventory_move = allow_metadata_inventory_move,
 	allow_metadata_inventory_take = allow_metadata_inventory_take,
 })
-
diff --git a/mods/default/nodes.lua b/mods/default/nodes.lua
index f7826e3f100b73f7fed3bfc3ccf866beafdaf6f3..c90c8dc42c8b3227d3d8e20f98fe17e1ea9b450f 100644
--- a/mods/default/nodes.lua
+++ b/mods/default/nodes.lua
@@ -1766,7 +1766,7 @@ minetest.register_node("default:lava_flowing", {
 -- Tools / "Advanced" crafting / Non-"natural"
 --
 
-local function get_chest_formspec(pos)
+function default.get_chest_formspec(pos)
 	local spos = pos.x .. "," .. pos.y .. "," .. pos.z
 	local formspec =
 		"size[8,9]" ..
@@ -1890,7 +1890,7 @@ function default.register_chest(name, d)
 			end
 			minetest.after(0.2, minetest.show_formspec,
 					clicker:get_player_name(),
-					"default:chest", get_chest_formspec(pos))
+					"default:chest", default.get_chest_formspec(pos))
 			open_chests[clicker:get_player_name()] = { pos = pos,
 					sound = def.sound_close, swap = name }
 		end
@@ -1912,7 +1912,7 @@ function default.register_chest(name, d)
 			minetest.show_formspec(
 				player:get_player_name(),
 				"default:chest_locked",
-				get_chest_formspec(pos)
+				default.get_chest_formspec(pos)
 			)
 		end
 		def.on_skeleton_key_use = function(pos, player, newsecret)
@@ -1957,7 +1957,7 @@ function default.register_chest(name, d)
 			end
 			minetest.after(0.2, minetest.show_formspec,
 					clicker:get_player_name(),
-					"default:chest", get_chest_formspec(pos))
+					"default:chest", default.get_chest_formspec(pos))
 			open_chests[clicker:get_player_name()] = { pos = pos,
 					sound = def.sound_close, swap = name }
 		end