Mozart lived in the 18th century and Berlioz lived in the 19th century.
Answer:
Movement. It is one of the Principles of Art.
Movement is a principle of design found in an artwork wherein its usage is to give the sensation of action by creating the look and feel of an action within the artwork. The movement found within the artwork will guide the viewer's eye to see the artwork as a whole and not by its pieces.
Other Principles of Art are Rhythm, Balance, Emphasis, Proportion, Gradation, Harmony, and Variety.
Source: Google search
I think it is colored lights illuminate the top during different occasions.
