From Leonardoís drawings and writings it emerges that one of the geniusís main interests was music. Of his many inventions, the mechanical drum is perhaps the most fascinating. There are two drawings of this instrument in the Atlantic Code: a pencil sketch (f. 877r) and a definitive drawing in red pastel (f. 837r). The drum was designed for a variety of occasions, from town parades to military actions. Two large rollers move the batons at the sides that beat the drum, and pegs on the rollers can be moved to set the rhythm.The player can move the drum along the ground, with the wheels activating the rollers, or play it standing still by turning a handle.