Underground

function stairsDown(n)
	for i=1, n do
		turtle.digDown()
		turtle.down()
		turtle.digDown()
		turtle.down()
		turtle.dig()
		turtle.forward()
	end
end

function digRoom(size)

	for k= 1, size do
		for j= 1, 4 do
			for i=1, size do
				turtle.dig()
				turtle.forward()
			end
			if k= size then
				turtle.placeDown()
			turtle.turnRight()
		end
	turtle.digUp()
	turtle.up()
	end



end

function mineShaft(size)
	for i=1, size do
		turtle.dig()
		turtle.forward()
		for j=1, 3 do

		-- dig layer
			turtle.turnLeft()
			turtle.dig()
			turtle.turnRight()
			turtle.turnRight()
			turtle.dig()
			turtle.turnLeft()
			turtle.digUp()
			turtle.up()
			if j==3 and (i%4==0) then
			-- every 4 movements forward and if  we are on the top layer place a light above
				turtle.down()
				turtle.placeUp()
			end
		end
			turtle.down()
			turtle.down()
			turtle.down()
		end
	end

end

stairsDown(3)
digRoom(4)
mineShaft(10)