level

function DigUp()
    while turtle.detectUp() do
        turtle.digUp()
    end
end

function DigDown()
    while turtle.detectDown() do
        turtle.digDown()
    end
end

function Dig()
    while turtle.detect() do
        turtle.dig()
    end
end

function Forward()
    while turtle.forward() == false do
        turtle.attack()
        turtle.dig()
    end
end

function CheckFuel()
    if turtle.getFuelLevel() < turtle.getFuelLimit() * 0.25 then
        print("Refueling...")
        while turtle.getFuelLevel() < turtle.getFuelLimit() * 0.75 do
            for i = 1, 16 do
                turtle.select(i)
                if turtle.refuel() then
                    break
                end
            end
        end
    end
end

function Step()
    print("Step")
    CheckFuel()
    DigUp()
    Dig()
    DigDown()
    turtle.forward()
end

local len = 16 * 16

while len > 0 do
    for i = 1, 2 do
        for ld = 1, len do
            Step()
        end
        turtle.turnRight()
    end
    len = len - 1
end