simple stairway
One or more straight stair flights, with successive flights vertically aligned and reached by walking back at each floor.
A simple stairway consists of one or more straight flights of stairs between levels. If there is more than one flight, the flights are vertically parallel to each other, so that the person climbing them must walk at each intermediate floor back to a starting point vertically aligned with that of the previous flight. This has the disadvantage of creating a longer route, although it is very simple to build and can be optimal for moving large pieces of furniture.
This form is somewhat more space-efficient than an alternating stairway, with the hidden cost however of requiring hallway space for the walk around the stairway at each intermediate floor. A hairpin staircase may generally achieve the same space efficiency, but it requires a wider space (more square in its proportions). Simple stairways can be suitable when only a narrow space is available.
For multiple floors, the next flight starts above the previous starting point. A climber therefore returns across the intermediate floor rather than continuing directly ahead as on a progressive stairway.
