qmark

-- solt1:under block
-- solt2:marker

-- 1 block 2 mark
function wing(block,mark)
	for i = 0, 61 do
		repeat
			turtle.dig()
		until turtle.forward()
	end
	repeat
		turtle.dig()
	until turtle.forward()
	turtle.select(block)
	turtle.placeDown()
	turtle.back()
	turtle.select(mark)
	turtle.place()
	for i = 0, 61 do
		turtle.back()
	end
end

local block = 0
local mark = 0

for i = 1, 16 do
	local ans = turtle.getItemDetail()
	if ans then
		if ans.name == "BuildCraft:Builders:markerBlock" then
			mark = i
		else
			block = i
		end
	end
end

if block == 0 or mark == 0 then
	write("need slot 1: Block\     slot 2: marker")
	block = 1
	mark = 2
end

wing(block,mark)
turtle.turnRight()
wing(block,mark)