Got a new Apple Pencil? Once the initial novelty wears off, you might find that it spends most of its time magnetically clipped to the side of your iPad Pro or, worse, stuck in the back of a drawer.

As we all possess a body, we think we know what it looks like. When we draw it, we bring to bear that prior knowledge and we draw that rather than the exactitude of the arm or leg that’s in front of ...