Learning brush strokes I

I was today looking at one of my glasses paintings I made in junior school years. I had drawn two butterflies with free hand using a black liner. While this is not something big I noticed, both the butterflies have different sizes and shapes but they have the same curves. The depth, the arcs at a very minute level (half a centimeter) reflect the same hand which drew them, anyone looking at the two pictures can infer it.

I wonder if there is a way to learn this. Not just learning what type of object it is or what species of butterflies it is but the curves, brush strokes and the drawing style which is very identifiable to a person and truly personalized. Learning the way different painters move their hands rendering every drawing ever created unique.

 

Hope to see more on it.