I was once at a tech-presentation where the presenter drew/wrote everything freehand like this on a tablet, almost similar to how one would use a blackboard. I

I was once at a tech-presentation where the presenter drew/wrote everything freehand like this on a tablet, almost similar to how one would use a blackboard. I really liked the way she presented compared to a static slide-deck, as she could adjust/add examples based on questions and feedback from the crowd.