turtle.select(1)
while true do
  sleep(0.1)
  turtle.select(2)
  if turtle.compareDown() then
  turtle.down()
  else
  turtle.select(1)
  if turtle.compare() then
  turtle.up()
  turtle.forward()
  else
  if turtle.compareDown() then
    turtle.forward()
  else
    turtle.back()
    turtle.turnRight()
    turtle.forward()
    if not turtle.compareDown() then
      turtle.back()
      turtle.turnRight()
      turtle.turnRight()
      turtle.forward()
      if not turtle.compareDown() then
        turtle.back()
        turtle.turnRight()
      end
    end
  end
end
end
end