the sudden spreading of the thing

Yes, wseiber, like a sudden coalescence or "crystallization".

If you think of crystallization in a laboratory beaker, one moment the solution is completely clear, add another drop, a single drop, and the next moment the solution is completely transformed into color.

In the blink of an eye
You'll let out a cry
"It's all crystal clear to me now!"

There are only six degrees of saturation separating the invisible world from the visible.