In folio 1062 recto (ca. 1497-1500) of the Codex Atlanticus, Leonardo presents the various mechanical wheels that he had studied thus far, featuring oscillating arms and running balls. He concludes his study by proposing a new perpetual-wheel system, set in motion by balls rolling from one end to the other of two straight channels interconnected to form a continuous course. These models are also reproduced and explained in the Forster II.