Final art VS sketches

I like to look back to past projects and see the evolution, sketches VS final art!Here are some illustrations from the book "Brain Stretchers-Logic Puzzles" published by Usborne.

The initial sketches are always done by pencil on paper and are very rough 😬 It's the brainstorming stage, where I get a general idea of what I'm going to draw and only then refine the sketches and send them to the client.