Here is a custom stair I made long ago, the arcs in the line of travel have a larger diameter than the distance between line of travel and the side of stairs.
The line of travel is also off center, otherwise the treads would become very large. This is all stair design basic rules, though. At least in NL (300 mm out of wall, etc etc).
Erwin Edel, Project Lead, Leloup Architectenwww.leloup.nl
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