octagon
A building plan with eight roughly equal sides, including sufficiently chamfered squares that appear octagonal.
An octagonal building plan has a perimeter with eight roughly equal sides meeting each other at similar convex angles. This form may be assigned to a square building with chamfered corners, as long as the chamfering is sufficient that the visual impression approximates a regular octagon.
The eight principal sides meet at similar convex angles. A square with chamfered corners can acquire that overall appearance when the chamfers are substantial enough.
Small chamfers can remain details of a square. The octagonal category requires a recognizable eight-sided impression; the circle category separately allows regular polygons with nine or more sides.
