How to Grow an Unstable Pattern
A gardener wants to grow a rare flower. Watering and fertilizing can't be done haphazardly; it must follow a strict schedule: a bit more warmth in the morning, a bit less moisture in the evening. Otherwise, the bed will be overrun by common weeds. Molecules on a metal surface behave in much the same way.
When organic molecules settle on a metal, they assemble into patterns, like pieces of a mosaic.