Patterns are formed by repeating elements. Repetition can become tiresome, so patterns are often used in the background rather than as the main focus. However, patterns can be exciting and interesting unto themselves.
Once you have established a pattern, you can create an anomaly. An anomaly is something unexpected and will draw attention to itself. It can be subtle or pronounced. There can be more than one. You can intentionally lull your audience into accepting a pattern, and just as they start to tire of it, hit them with a bold anomaly.