Final answer:
A special mirror, known as a moving mirror, can be used in light shows with lasers to create colorful effects. When a light ray is reflected from a moving mirror that has been rotated by an angle, the direction of the light ray changes by 20 degrees.
Step-by-step explanation:
A special mirror, known as a moving mirror, can do more than just reflect physical features. In the context of light shows staged with lasers, moving mirrors are used to swing beams and create colorful effects. When a light ray is reflected from a moving mirror that has been rotated by an angle, the direction of the light ray changes by 20 degrees.