--up is powder
--front is concrete
while true do
	--pick up concretepowder
	turtle.select(1)
	if turtle.getItemCount(1) > 0 then
		-- is it powder?
		local item = turtle.getItemDetail(1)
		if item and item.name == "minecraft:concrete_powder" then
			turtle.placeDown()
			sleep(0.1)
			turtle.digDown()
		else
			turtle.drop()
		end
	elseif turtle.getItemCount(16) > 0 then
		for i = 2, 16 do
			turtle.select(i)
			turtle.drop()
		end
	else
		turtle.suckUp()
	end
end