n = 50
z = 3
--------------------------
function dig(n)
    for i=1, n do
        turtle.dig()
        turtle.digUp()
        turtle.digDown()
        turtle.forward()
    end
end
--------------------------
dig(n)
--------------------------
turtle.turnLeft()
dig(z)
turtle.turnLeft()
--------------------------
dig(n)
--------------------------
turtle.select(16)
turtle.place()
turtle.drop()