Sketch

A sketch is a rapidly executed freehand drawing that is not usually intended as a finished work.A sketch may serve a number of purposes: it might record something that the artist sees, it might record or develop an idea for later use or it might be used as a quick way of graphically demonstrating an image, idea or principle.

There are a lot of medium that could be used for the sketch art – pen, pencil, charcoal being few of them