A center is a organized zone of space.
A center is an organized zone of space. It is a focal point that draws your attention. Obvious centers are objects: a fireplace in a room. an alter in a church, a window. It can also be empty space. In this mosque the large empty square is the major center.
A strong center often has borders and smaller scale centers that support it as in this plate.
When you become sensitive to recognizing centers, you will recognize that they have different degrees of aliveness or pregnancy and usefulness. You will recognize centers nested within each other and making up larger zones of space. Compare these two house plans. The first one (by F.L. Wright) has stronger centers that are more "alive" than does the second. It is more alive because the different spaces all complement each other in their differences in scale and because there are local symmetries within the overall plan.
A strong center also has a good shape which is pleasing to the eye and helps create next to it another space which is a center, and, it too, has a good shape. Look at this well known cut out by Matisse. Not only does each blue center have a good shape that contributes to the overall center (the figure) but the white spaces inbetween are also positively shaped.
In the Indian Story of Indra's Net, Indra has a wonderful net and at each intersection there is a jewel. Each jewel makes the surrounding jewels shine more brightly and makes the net more wonderful. Successful centers will be like jewels in the net, beautiful in and of themselves and complementing and strengthening the beauty of the whole.
