function refuel()
    turtle.select(1)
    while (turtle.refuel(1)) do end
end

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

    turtle.forward()

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

    turtle.digDown()
end

function dig_layer()
    dig_col()
    turtle.turnLeft()
    dig_col()
    turtle.turnRight()
    turtle.turnRight()
    turtle.forward()
    dig_col()
    turtle.turnRight()
    turtle.turnRight()
    turtle.forward()
    turtle.turnRight()
end

refuel()
turtle.up()
torches = turtle.getItemCount(2)
for i=1,torches do
    dig_layer()
    dig_layer()
    dig_layer()
    dig_layer()
    dig_layer()
    turtle.turnRight()
    turtle.forward()
    while(turtle.detect())
    do
        turtle.dig()
    end
    turtle.select(3)
    turtle.place()
    turtle.back()
    turtle.select(2)
    turtle.place()
    turtle.turnLeft()
end