The magnetic pen is simply a piece of plastic with a small magnet in the tip. The field of the magnetic pen is strong enough to penetrate the plastic and pull the particles through the thick liquid.
The magnetic pen is ergonomically styled so that anyone, especially little children, can grip it comfortably. The pen is usually tied to the Magna Doodle by an attached string. Some Magna Doodles also come with "shape stampers," which are simply magnets in shapes like diamonds, triangles and circles.
Writing is but one use of the Magna Doodle. You must also be able to erase it, so let's look at the eraser.