On: The Spiral Staircase Myth (2020)

[jamincan]

For the person facing up, their opponent is to their right, which is closed off. They would need to reach up and to the right, and that motion would be blocked by the newel post.

For the person facing down, their opponent is to their left, which is open. They would need to reach down and across their body to the left, unobstructed.