To defuse the explosive device shown in the figure on the right, you must press 8 buttons in the correct order until you reach the 'PRESS' button. Each button can only be pressed once. The "U" on the buttons indicates moving up, "D" means down, "L" means left, and "R" means right. The number on each button indicates the number of moves. Which button must you press first? This problem may seem difficult at first glance, but it is actually quite simple, mainly testing your observational skills and ability to integrate information. Here's a hint: 1. Straight-line movement 2. The final step involves pushing upwards (reverse thinking). Hookle solved it this way.