Moderation

A teaching material in Ashikaga Gakko (Japan) to teach students the importance of moderations. The cup is inclined when it's empty. When you pour water into it, it goes upright. If you pour more water, it becomes inclined again.

Moderation is the process or trait of eliminating, lessening, or avoiding extremes. It is used to ensure normality throughout the medium on which it is being conducted. Common uses of moderation include: