diff --git a/create_catalog.lua b/create_catalog.lua
index 5cff333..8267068 100644
--- a/create_catalog.lua
+++ b/create_catalog.lua
@@ -25,7 +25,7 @@ function mapblock_lib.create_catalog(filename, pos1, pos2, options)
 
 	-- default to async serialization
 	options = options or {}
-	options.delay = options.delay or 0.2
+	options.delay = options.delay or 0.1
 	options.callback = options.callback or function() end
 	options.progress_callback = options.progress_callback or function() end
 
diff --git a/get_catalog.lua b/get_catalog.lua
index 224b713..81d41fb 100644
--- a/get_catalog.lua
+++ b/get_catalog.lua
@@ -136,7 +136,7 @@ function Catalog:deserialize_all(target_mapblock_pos, options)
 	local count = 0
 
 	options = options or {}
-	options.delay = options.delay or 0.2
+	options.delay = options.delay or 0.1
 	options.rotate_y = options.rotate_y or 0
 	options.callback = options.callback or function() end
 	options.progress_callback = options.progress_callback or function() end
diff --git a/init.lua b/init.lua
index 6b0c59f..4d00370 100644
--- a/init.lua
+++ b/init.lua
@@ -23,6 +23,7 @@ dofile(MP .. "/util.lua")
 dofile(MP .. "/pointed.lua")
 dofile(MP .. "/pos.lua")
 dofile(MP .. "/data.lua")
+dofile(MP .. "/metadata.lua")
 
 dofile(MP .. "/mapblock.lua")
 
diff --git a/metadata.lua b/metadata.lua
new file mode 100644
index 0000000..da057a1
--- /dev/null
+++ b/metadata.lua
@@ -0,0 +1,41 @@
+
+local function update_formspec(meta)
+    local group = meta:get_string("group")
+    -- TODO
+
+    meta:set_string("formspec", [[
+        size[10,8.3]
+        real_coordinates[true]
+        field[0.1,0.4;8.8,0.8;group;Group;]] .. group .. [[]
+        button_exit[9,0.4;0.9,0.8;set;Set]
+        list[context;main;0.1,1.4;8,1;]
+        list[current_player;main;0.1,3;8,4;]
+        listring[]
+    ]])
+end
+
+minetest.register_node("mapblock_lib:metadata", {
+	description = "Mapblock-lib metadata marker",
+	tiles = {"mapblock_lib_metadata.png^[colorize:#23c1cc"},
+    drawtype = "allfaces",
+    use_texture_alpha = "blend",
+    paramtype = "light",
+    paramtype2 = "facedir",
+    sunlight_propagates = true,
+	groups = {
+		oddly_breakable_by_hand = 3
+	},
+
+	on_construct = function(pos)
+		local meta = minetest.get_meta(pos)
+        update_formspec(meta)
+	end,
+
+    on_receive_fields = function(pos, _, fields)
+        if fields.set then
+            local meta = minetest.get_meta(pos)
+            meta:set_string("group", fields.group)
+            update_formspec(meta)
+        end
+    end
+})
diff --git a/readme.md b/readme.md
index 6245300..e237627 100644
--- a/readme.md
+++ b/readme.md
@@ -64,7 +64,7 @@ local mb_pos1 = { x=0, y=0, z=0 }
 local mb_pos2 = { x=1, y=1, z=1 }
 local options = {
     -- optional: delay between operations
-    delay = 0.2,
+    delay = 0.1,
     -- optional: called when done
     callback = function()
         print("done!")
diff --git a/textures/mapblock_lib_metadata.png b/textures/mapblock_lib_metadata.png
new file mode 100644
index 0000000..7beae93
Binary files /dev/null and b/textures/mapblock_lib_metadata.png differ