Insert a plotter point in the lower left leg of the pantograph. Insert a pen or pencil in the lower right leg. Anchor the lower center pivot of the parallelogram to the drawing surface. Trace over an original drawing or diagram with the plotter point. The pencil at the right will create a copy of the same size.
Switch the plotter point to the lower center pivot of the parallelogram. Anchor the lower left leg to the surface. Tracing over the original art with the plotter point will now create an enlarged version of the subject at the pencil end on the right. To increase the scale of the enlargement, adjust the sides of the pantograph to make the parallelogram larger.
Switch the points so that the pencil is in the lower center position and the plotter point is on the right. Anchor the lower left leg. Tracing over the original art with the plotter now produces a smaller version from the pencil in the center. Adjust the size of the parallelogram to determine the reduction.