iter = 20
cur_iter = 1
while cur_iter <= iter do
  turtle.refuel()
  turtle.dig()
  turtle.forward()
  turtle.select(2)
  turtle.place()
  turtle.placeDown()
  turtle.turnLeft()
  turtle.place()
  turtle.turnRight()
  turtle.turnRight()
  turtle.dig()
  turtle.place()
  turtle.turnLeft()
  turtle.digUp()
  turtle.up()
  turtle.place()
  turtle.turnLeft()
  turtle.place()
  turtle.turnRight()
  turtle.placeUp()
  turtle.turnRight()
  turtle.dig()
  turtle.place()
  turtle.turnLeft()
  turtle.down()
  cur_iter = cur_iter + 1
end