A simple technique for clarification

I have this client now who has simple but very effective techniques to clarify things and express his concerns. He opens a Microsoft Paint instance and starts drawing.

He shares the screen with me and, with simple shapes, describes what I presented him, asking questions. Then he passes to express his concerns and makes his change requests.

And then I have another iteration to work on. No need for complex software or subscriptions. MS Paint and simple shapes are more than enough to discuss anything. God bless this simple but effective techniques.