interlaced angular helix stairway

An interlaced angular helix stairway consists of two (or possibly more) angular helix stairways interlaced with each other in the same shaft or vertical space. This form of stairway is not very common. Like an interlaced helix, it can be used to accommodate bi-directional travel, with one of the stairways designated for climbing and the other for descending.

Each interwoven route follows an angular helix. Sharing a shaft alone is insufficient unless the stairways are threaded together in that arrangement.

Separate upward and downward travel is a possible use rather than a requirement. More than two interlaced stairways are included.