scaling ladder
This ladder was used to climb walls of enemy towers. The difference between a regular ladder and a scaling ladder is a scaling ladder can be raised or lowered. It is similar to the invention that firefighters use to get into houses or to save a kitten from a tree. Today the scaling ladder works very different then the one Leonardo designed. Today's scaling ladder has two or more ladders attached to each other. You can raise and lower the second ladder to make the ladder go higher. Leonardo's ladder had gears that would raise or lower the ladder. There is very little known about the scaling ladder that Leonardo designed.