From the kit description:
When the handle is turned the artist looks up at his model, then down at his easel and -amazingly- he starts to draw. Keep turning and you'll be amazed to see that he actually does a real pencil drawing of the model on a 'post-it' note! Although the model of the artist, the lady and all the little accessories (Paints, brushes,etc) are detailed and amusing, the real complexity lies within the case under their feet. The handle operates a 'worm' gear which in turn drives two large cams. One controls the forwards-and-backwards movement of the artist's arm, the other the 'side-to-side' movements. A series of levers transmit the movements and the combination of both actions results in the drawing.
Here's the link to The Artist Automaton kit page.