Revolving bridge with parabolic profile

This is a model of one of the many "very light yet rugged" bridges described by Leonardo in his letter to Ludovico il Moro. These bridges were designed for construction with material that was readily available and easy to transport. The bridge with a parabolic profile has only one span and is secured to the two banks by means of a large vertical pin. It is moved by means of ropes and hoists, aided by wheels and metal rollers in performing its sliding motion. Moreover, the bridge is equipped with a counterweight tank for balancing and manoeuvring purposes, while suspended in the air before being laid down on the opposite bank.