The slender mirror visually gives people the feeling of longitudinal stretching, while the wide mirror visually produces transverse stretching. More importantly, using the principle of optical refraction, the convex mirror with thin side and thick middle can reduce the lateral proportion of imaging, while the concave mirror with thin middle and thick upper and lower ends can lengthen the vertical direction of imaging, which can both produce slimming effect. It's just that the radian of these concave mirror is very small, which is not easy for the naked eye to detect.

Precautions for installing fitting glasses:

1. Mirrors are afraid of moisture, because mirror glass is usually cut before use. Water vapor will easily enter the mirror surface from the side cut by glass cutter, which will corrode the mirror surface and produce mildew and rust spots. Therefore, after buying a mirror, you might as well paint one side of the mirror and the back at the same time.

2. The fitting mirror can be installed behind the indoor door, the bedroom door or the living room door. These are the common positions of the fitting mirror. First, it is convenient to check the appearance before going out, and second, the installation position is hidden, which meets the requirements of metaphysics for mirror geomantic omen and avoids unnecessary reflection, thus affecting home geomantic omen.