Most likely a cropped page from a notebook, this sheet vividly illustrates the parallel paths of Leonardo's artistic and scientific genius. The recto depicts at the top three sketches of the centrifugal swirling movement of water around obstacles (probably the thin wood piers of a bridge). Below are a view of water flowing by a wood bridge and, to the right, a slender nude man unsheathing a sword. At the bottom the classical hero Hercules is seen from the front holding a club. On the verso Hercules is shown from the rear.

The sheet can be dated to 1506–8, shortly after Leonardo stopped work on the Battle of Anghiari cartoon and mural for the Great Council Hall of the Palazzo Vecchio, Florence. The drawings of Hercules were apparently intended for an unexecuted statue. In representing him holding the club horizontally, Leonardo reinvented Hercules as an icon of preparedness, not unlike the symbolic allusion to civic vigilance evoked in Michelangelo's monumental marble David of 1501–4 (Gallerie dell'Accademia, Florence), which at the time was placed at the entrance of the Palazzo Vecchio. Considering the spirited professional interaction between the two artists during these years, it may well be that Leonardo conceived of his Hercules with a public function in mind and in competition with Michelangelo's David.