Alright, as I figured, it turns out that it is algorithmically generated, as I went through the disassembly I have of it and discovered various subroutines that poll 3 byte locations and store them in the playfield registers. I'd assume that changing the maze layout would involve rewriting these sections to display the desired layout. Tried changing the values in one of these tables and 8 sections of the maze changed. So, you're right, Nukey Shay, it is mirrored down 4x and reflected. Even though the maze changed, the ghosts and the pac man all followed their original paths so there is probably another set of routines or a table that determines the valid paths at any given location. I admit that yes, it is a "turd" of a rom, but I guess if I study it I'll learn how NOT to write an Atari game!