exc

length=30
width=40
depth=15

function dig()
  i=length
  repeat
    turtle.dig()
    turtle.forward()
    i=i-1
    until i==0
    end

function lback()
  i=length
  repeat
    turtle.back()
    i=i-1
    until i==0
  end

function digw()
turtle.turnRight()
turtle.dig()
turtle.forward()
turtle.turnLeft()
end

function plane()
dig()
lback()
w=width
repeat
  digw()
  dig()
  lback()
  w=w-1
  until w==1
w=width
repeat
  turtle.turnLeft()
  turtle.forward()
  w=w-1
  until w==1
turtle.turnRight()
  end

  plane()