Roller coasters, it is a very exciting entertainment tool, found in amusement parks and theme parks, is a use of gravity and inertia to make train travel along a winding machine. A basic roller coaster structure contains the climb, slide, reverse, its orbit design is not necessarily a complete circle back, also can design for the car body in orbit operation mode for moving back and forth, most of the roller coaster of every car can accommodate 2, 4 or 6 people, the car use hook connected each other, just like a train.