Designers often think up of ingenious ways to redefine common place products and items. See for example this foldable staircase design from industrial designer Aaron Tang. Though it basically looks and functions as a staircase, Aaron calls it a ‘redefined door’ as it is “an element of a wall that allowed passageway to another environment when opened and restricted passageway when closed.”
Using just hinges and pistons, the staircase can fold up a wall to expand space on the lower level or restrict access to the upper level. Aaron’s staircase is designed to be closed or opened from upstairs and downstairs.