Placing an order at the 91,000 price level, as long as there is a transaction, you can basically catch a rebound trend. The needle-picking method is still quite reliable, but the problem is that you often can't wait for that opportunity. The market is volatile, and sometimes before you can react, the order is already filled, or the price just jumps past without allowing you to place an order. That's why many people know this trick but can't make money—timing really depends on luck.