local sizeX, sizeY
local curX = 0, curY = 0
local slot = 1

sizeX, sizeY = ...
turtle.select(slot)


while true do

	while turtle.getItemCount(slot) == 0 do
		slot = slot % 16 + 1
		turtle.select(slot)
		sleep(0)
	end
	turtle.placeDown()

	if curX % 2 == 0 then
		if curZ == sizeZ - 1 then
			if curX == sizeX - 1 then
				return
			else
				turtle.turnRight()
				while not turtle.forward() do sleep(0) end
				turtle.turnRight()
				curX = curX + 1
			end
		else
			curZ = curZ + 1
			moveForward()
		end
	else --  curX % 2 ~= 0

		if curZ == 0 then
			if curX == sizeX - 1 then
				return
			else
				turtle.turnLeft()
				while not turtle.forward() do sleep(0) end
				turtle.turnLeft()
				curX = curX + 1
			end
		else
			curZ = curZ - 1
			while not turtle.forward() do sleep(0) end
		end

	end

end