You may also be interested in Uniform tilings in the hyperbolic plane. In this non-euclidean plane, regular pentagon tiling is possible, and, using some mapping to Euclidean space, aesthetically pleasing pictures may be produced.
So we may presume the hallway in question had a vaulted ceiling.
Or that Hogwarts is doing funny things with space, which we know it does regularly.
You may also be interested in Uniform tilings in the hyperbolic plane. In this non-euclidean plane, regular pentagon tiling is possible, and, using some mapping to Euclidean space, aesthetically pleasing pictures may be produced.
So we may presume the hallway in question had a vaulted ceiling.
Or that Hogwarts is doing funny things with space, which we know it does regularly.