I'm trying to look for a map, I have no idea how old it is. I remember fairly flat textures and VERY weird gameplay. It was one of the few attempts at non-euclidean geometry in jump I believe. I remember an experienced mapper made it but I looked through my post history and couldn't find anything there.
I remember one part of it had floors that curved downwards gradually at a 90 degree angle and if you walked towards it, it was as if you were walking straight down. This was one of the core features of the map I believe