This bridge was designed to be erected quickly under battle conditions.
Leonardo’s idea was that it could be constructed by a group of soldiers in an
emergency using small tree trunks found on the edge of a river.
The trunks are interwoven and braced without the use of ropes or nails in such a
way that the more downward pressure is applied, the more the braced pieces
of wood interlock and the more secure the construction is. Leonardo called it a
bridge of ‘Safety’.