Stair Santos Dumont is a kind of ladder made to occupy half the space that would take up a normal ladder. The shape of alternating steps makes the space occupied by each floor stair climb two steps enable (must be careful to only step on the first rung). It's called a ladder Santos Dumont, since this was the Brazilian who created early last century to use in your own home in Brazil, where it is often used to access mezzanines, lofts and other places of little traffic and only one person rises each time.