I just realized a possible reason for why the ropes around the pole in the Arma Christi are sometimes helical twined!
It's the same reason the sword in the list of the Arma Christi implements is sometimes marked with an X. Helical twining also creates an X shape. X marks the spot (it is a symbol of betrayal). It would help to iconographically distinguish the pole from a regular architectural column or pole (or maybe the artists just thought it looked cooler).
It's the same reason the sword in the list of the Arma Christi implements is sometimes marked with an X. Helical twining also creates an X shape. X marks the spot (it is a symbol of betrayal). It would help to iconographically distinguish the pole from a regular architectural column or pole (or maybe the artists just thought it looked cooler).

