A loudspeaker which emits sound of frequency 1000 Hz is placed several meters from a planereflecting wall in a large chamber containing a gas.
扬声器发射的声音频率1000赫兹是放置数米，从平面反映墙在一个大型会议厅，载有天然气。
2
The angular displacement of reflecting surface is measured in accordance with the direction change of Moire fringes caused by the inclination of grating. self-imaging plane.
利用光栅自成象面的倾斜引起莫尔条纹方向变化来测量反射表面的角位移。
3
The art of calligraphy shows a process reflecting and concretizing a solid line on a two dimensional plane in a period of time. This kind of visual art also has the traits of the art of the time.