The figure 8 refers to two straight lines that are parallel to each other but slightly inclined inward, and the shape is similar to the number 8. In an automobile, the rearview mirror is designed to have such a shape. This design can provide a wider field of vision, allowing drivers to observe the side and rear traffic conditions. By adjusting the two rearview mirrors to be parallel to the road surface and slightly inclined inward, the blind area can be minimized and the safety and driving comfort can be improved.