Breaking the Pattern
Introducing a single element that interrupts an otherwise regular repetition, creating an immediate focal point.
In depth
The visual system is efficient at detecting anomalies, so a break in a pattern is found before the pattern itself is consciously registered. This makes it one of the most reliable ways to construct a picture: establish the rhythm, then place one thing that disobeys it. The break need only be small to dominate.
Examples in practice
One open window in a facade of closed ones becomes the subject of the photograph without any other emphasis.