What type of bridge did Leonardo da Vinci design to assemble without fasteners or supports?

Leonardo da Vinci designed a self-supporting bridge that could be assembled without fasteners or permanent supports.

The design uses interlocking timbers arranged so that the weight of each piece helps hold the structure together. This made it portable and relatively quick to assemble, useful qualities for military engineers who needed temporary crossings. Leonardo recorded the concept in his notebooks while studying practical engineering and military technology.

It is often called a self-supporting or self-locking bridge, but it should not be confused with a modern suspension bridge or a pontoon bridge. Leonardo’s drawing represents an engineering concept rather than evidence that he built a full-scale version. Modern demonstrations show that the arrangement can work when the pieces are cut and positioned correctly.