For me it's due to the feedback loop: head instructs the hands, hands draw the diagrams, eyes read the diagram back in, head reprocessed the diagram, rinse and

For me it's due to the feedback loop: head instructs the hands, hands draw the diagrams, eyes read the diagram back in, head reprocessed the diagram, rinse and repeat. It's also why writing revision material out in long hand helped it persist in my memory back when I last studied