diff --git a/maidroid/script/instruction_set_doc.lua b/maidroid/script/instruction_set_doc.lua
new file mode 100644
index 0000000..a3a2356
--- /dev/null
+++ b/maidroid/script/instruction_set_doc.lua
@@ -0,0 +1,23 @@
+-- See also the pdisc mod's instruction list.
+
+local instr = {
+	{"getpos", "<v x>, <v y>, <v z>", "Gets the maidroid's position."},
+	{"getvelocity", "<v x>, <v y>, <v z>", "Gets the maidroid's velocity."},
+	{"getacceleration", "<v x>, <v y>, <v z>", "Gets the maidroid's acceleration."},
+	{"getyaw", "<v yaw>", "Gets the maidroid's yaw."},
+
+
+	{"setyaw", "<n yaw>", "Sets the maidroid's yaw in radians."},
+
+	{"jump", "[<n heigth>]", "Makes the droid jump, if height is invalid (height ∈ ]0,2]), it's set to 1, if it's a variable, it's set to a bool indicating whether the jump succeeded."},
+	{"beep", "", "Execute this every second while the droid walks backwards, pls."},
+}
+
+o = "Instructions:\n\n"
+for i = 1,#instr do
+	i = instr[i]
+	o = o .. i[1] .. "  " .. i[2] .. "\n"
+		.. "  " .. i[3] .. "\n\n" -- TODO: max 80 letters each line
+end
+
+print(o)
diff --git a/maidroid_core/cores/ocr.lua b/maidroid_core/cores/ocr.lua
new file mode 100644
index 0000000..6301df1
--- /dev/null
+++ b/maidroid_core/cores/ocr.lua
@@ -0,0 +1,166 @@
+------------------------------------------------------------
+-- Copyright (c) 2016 tacigar. All rights reserved.
+-- https://github.com/tacigar/maidroid
+------------------------------------------------------------
+
+local maidroid_instruction_set = {
+	-- popular (similars in lua_api) information gathering functions
+	getpos = function(_, thread)
+		local pos = thread.droid.object:getpos()
+		return true, {pos.x, pos.y, pos.z}
+	end,
+
+	getvelocity = function()
+		local vel = self.vel
+		return true, {vel.x, vel.y, vel.z}
+	end,
+
+	getacceleration = function(_, thread)
+		local acc = thread.droid.object:getacceleration()
+		return true, {acc.x, acc.y, acc.z}
+	end,
+
+	getyaw = function(_, thread)
+		return true, thread.droid.object:getyaw()
+	end,
+
+	-- other info functions
+
+	-- popular actions for changing sth
+	setyaw = function(params, thread)
+		if #params ~= 1 then
+			return false, "wrong number of arguments"
+		end
+		local p = params[1]
+		if type(p) ~= "number" then
+			return false, "unsupported argument"
+		end
+		thread.droid.object:setyaw(p)
+		return true
+	end,
+
+	-- other actions
+	jump = function(params, thread)
+		-- test if it can jump
+		local droid = thread.droid
+		if droid.vel.y ~= 0
+		or droid.vel_prev.y ~= 0 then
+			return true, false
+		end
+
+		-- get the strength of the jump
+		local h = tonumber(params[1])
+		if not h
+		or h <= 0
+		or h > 2 then
+			h = 1
+		end
+
+		-- play sound
+		local p = droid.object:getpos()
+		p.y = p.y - 1
+		local node_under = minetest.get_node(p).name
+		local def = minetest.registered_nodes[node_under]
+		if def
+		and def.sounds then
+			local snd = def.sounds.footstep or def.sounds.dig
+			if snd then
+				p.y = p.y + .5
+				minetest.sound_play(snd.name, {pos = p, gain = snd.gain})
+			end
+		end
+
+		-- perform jump
+		droid.vel.y = math.sqrt(-2 * h * droid.object:getacceleration().y)
+		droid.object:setvelocity(droid.vel)
+		return true, true
+	end,
+
+	beep = function(_, thread)
+		minetest.sound_play("maidroid_beep", {pos = thread.droid.object:getpos()})
+		return true
+	end,
+}
+
+
+local function mylog(log)
+	-- This happens to the maidroids messages
+	minetest.chat_send_all("maidroid says " .. log)
+end
+
+-- the program is loaded from a "default:book_written" with title "main"
+-- if it's not present, following program is used in lieu:
+local dummycode = [[
+beep
+print $No book with title "main" found.
+]]
+
+local function get_code(self)
+	local list = self:get_inventory():get_list"main"
+	for i = 1,#list do
+		local stack = list[i]
+		if stack:get_name() == "default:book_written" then
+			local data = minetest.deserialize(stack:get_metadata())
+			if data
+			and data.title == "main" then
+				return data.text
+			end
+		end
+	end
+end
+
+local function on_start(self)
+	self.object:setacceleration{x = 0, y = -10, z = 0}
+	self.object:setvelocity{x = 0, y = 0, z = 0}
+	self.vel = {x = 0, y = 0, z = 0}
+	self.vel_prev = self.vel
+
+	local parsed_code = pdisc.parse(get_code(self) or dummycode)
+	self.thread = pdisc.create_thread(function(thread)
+		thread.flush = function(self)
+			mylog(self.log)
+			self.log = ""
+			return true
+		end
+		table.insert(thread.is, 1, maidroid_instruction_set)
+		thread.droid = self
+	end, parsed_code)
+	self.thread:suscitate()
+end
+
+local function on_step(self)
+	local thread = self.thread
+	if not thread.stopped then
+		return
+	end
+	self.vel_prev = self.vel
+	self.vel = self.object:getvelocity()
+
+	thread:try_rebirth()
+end
+
+local function on_resume(self)
+	self.thread:continue()
+end
+
+local function on_pause(self)
+	self.thread:flush()
+end
+
+local function on_stop(self)
+	self.thread:exit()
+	self.thread = nil
+
+	self.object:setvelocity{x = 0, y = 0, z = 0}
+end
+
+-- register a definition of a new core.
+maidroid.register_core("maidroid_core:ocr", {
+	description      = "OCR programmable maidroid core",
+	inventory_image  = "maidroid_core_ocr.png",
+	on_start         = on_start,
+	on_stop          = on_stop,
+	on_resume        = on_resume,
+	on_pause         = on_pause,
+	on_step          = on_step,
+})
diff --git a/maidroid_core/depends.txt b/maidroid_core/depends.txt
index 2c64b95..d846d9e 100644
--- a/maidroid_core/depends.txt
+++ b/maidroid_core/depends.txt
@@ -1 +1,2 @@
 maidroid
+pdisc?
diff --git a/maidroid_core/init.lua b/maidroid_core/init.lua
index a8af579..7d16105 100644
--- a/maidroid_core/init.lua
+++ b/maidroid_core/init.lua
@@ -12,3 +12,6 @@ dofile(maidroid_core.modpath .. "/cores/_aux.lua")
 dofile(maidroid_core.modpath .. "/cores/empty.lua")
 dofile(maidroid_core.modpath .. "/cores/basic.lua")
 dofile(maidroid_core.modpath .. "/cores/farming.lua")
+if pdisc then
+	dofile(maidroid_core.modpath .. "/cores/ocr.lua")
+end
diff --git a/maidroid_core/sounds/maidroid_beep.ogg b/maidroid_core/sounds/maidroid_beep.ogg
new file mode 100644
index 0000000..c896836
Binary files /dev/null and b/maidroid_core/sounds/maidroid_beep.ogg differ
diff --git a/maidroid_core/textures/maidroid_core_ocr.png b/maidroid_core/textures/maidroid_core_ocr.png
new file mode 100644
index 0000000..e4f33b8
Binary files /dev/null and b/maidroid_core/textures/maidroid_core_ocr.png differ
diff --git a/maidroid_core/xcf/maidroid_core_ocr.xcf b/maidroid_core/xcf/maidroid_core_ocr.xcf
new file mode 100644
index 0000000..459f886
Binary files /dev/null and b/maidroid_core/xcf/maidroid_core_ocr.xcf differ
diff --git a/maidroid_tool/core_writer.lua b/maidroid_tool/core_writer.lua
index 209ece5..876ab84 100644
--- a/maidroid_tool/core_writer.lua
+++ b/maidroid_tool/core_writer.lua
@@ -8,6 +8,7 @@ do -- register core writer
 	local dye_item_map = {
 		["dye:red"]    = "maidroid_core:basic",
 		["dye:yellow"] = "maidroid_core:farming",
+		["dye:white"] = "maidroid_core:ocr",
 	}
 
 	local node_box = {