This plotter drawing is by an unknown artist, and was created using a computer and a pen plotter. A plotter is a mechanical device that is linked to a computer and guides a pen or brush across the drawing surface. Alternatively, some plotters use a static pen, but move the paper underneath. A computer program written by the artist, sometimes in collaboration with a computer programmer, would act as a set of instructions that would drive the pen across the drawing surface and dictate its route. Pen plotters were one of the few output devices available in the early stages of computer technology, but they are still used by some artists today.