What kind of light does 'shimmer' describe?

The term 'shimmer' evokes an image of light that is not steady or strong but rather weak and tremulous. It describes a flickering or wavering quality, often associated with light reflecting off a surface, creating a sparkling effect. This kind of light can be observed, for example, on water's surface when it is disturbed by a gentle breeze or in the way sunlight dances on a polished surface. The essence of 'shimmer' captures that delicate, transient quality that is best represented by a weak and tremulous light, which contrasts with strong, constant, or focused lights suggested in the other choices.