Transitions. Staircases serve such a conventional purpose. They’re locomotive, they bring us from one floor to the next, they’re much safer than an elevator in a fire. They need not be decorative; they might be tucked into a corner, disguised. But they can also be a canvas for artistic embellishment, the centerpiece in the foyer of a manse conceived of and constructed to make a statement, or an agent of deception. Allegedly, the double-helic staircase in Chateau de Chambord (shown above) in the Loire Valley was built so that the mistress could descend from the Lord’s stateroom without being intercepted by the wife as she returned home.