progressive stairway
Multiple stair flights continuing along one straight route through successive levels without requiring a turn.
A progressive stairway consists of multiple flights of stairs arranged in a continuous straight line, serving different levels without requiring the climber to turn. This form is common for outdoor staircases but unusual inside buildings because it requires substantial horizontal space, and also requires significant variations in floor plans for different floors. It can be used to create a ceremonial or architectonically impressive sense of progression.
The next flight continues ahead rather than starting after a return walk. That distinguishes the route from a simple stairway with vertically aligned flights.
Outdoor use is common but is not mandatory. An interior arrangement remains progressive when its successive flights maintain the continuous straight route.
