Do you still remember the pull-tab spring coils you played with when you were a child? I believe many people born in the 1980s still remember it. Now this thing has a more interesting way to play. The foreigner puts it on a micro "treadmill" with a slope, starts the treadmill, and the spring will "run" hard without interruption. As shown in the picture above, it looks very interesting. If you build a large one and place it at the entrance of the supermarket, it will be very eye-catching.