Honestly I don't know. I do believe iClassic was originally based on Storm's overworld that they had laying around(not to be confused with Thor's, which is the current Classic PC overworld). However when the overworld was first put on iClassic it was just a few levels, like Graal City and Swamp town. After levels started being added on from that it most likely took on its own form, rather than just copy/pasting the entire overworld layout from Storm's. Pretty sure it's starting to take the shape more similar to Tyhm's version now, though.