A similar case can be applied to Midway creating Ms. Pac-Man and other Pac-Man sequels without Namco's permission.
It started when GCC programmers made a Pac-Man conversion kit under the primordial name Crazy Otto, development of which occurred after GCC and Atari had settled a lawsuit over a Missile Command conversion kit called Super Missile Attack. Part of the settlement meant GCC could not sell conversion kits without consent from the original manufacturer. But rather than completely shelve Crazy Otto, the programmers presented the game to Midway, which came up with several renames prior to Ms. Pac-Man.
Midway waited impatiently over Namco's next Pac-Man sequel that ultimately became Super Pac-Man. Instead, they reverse-engineered the Pac-Man code to turn it into Ms. Pac-Man. The same thing was done for Pac-Man Plus, Baby Pac-Man and Jr. Pac-Man and, bizarrely, Professor Pac-Man, which ultimately had terminated the relationship between Midway and Namco and ultimately both Midway and GCC ended up having to sell their rights to the Pac-Man series back to Namco.
~Ben