field

function stack()
  turtle.dig()
  turtle.forward()
  while turtle.detectUp() do
    turtle.digUp()
    turtle.up()
  end
  if turtle.detectUp() == false then
    turtle.down() until == false
  end
end

function line()
  for i=1,100 do
    stack()
  end
end
for i=1,50 do
  line()
  turtle.turnLeft()
  turtle.forward()
  turtle.turnLeft()
  line()
  turtle.turnRight()
  turtle.forward()
  turtle.turnRight()
  line()