Lloyd Alter is Design Editor for Treehugger and teaches Sustainable Design at Ryerson University in Toronto. Alternating tread stairs are terrific for saving space; you only put one foot on a tread at ...

Posts shared in early March 2021 claim that alternate-tread staircases are called “Witches Stairs,” allegedly built with the belief that “witches can’t climb up them.” This claim is false, as ...