Copyright it's a total crap from the big companies.
As you are not using any method to steal the actual graphics from the software or the hardware you can create anything.
A circle with a mouth was a great idea for the hardware of the 80's also a triangle for a spaceship was the minimmum and the best for asteroids.
You cannot create a circle with a triangle for mouth and call it pac-man... after all the copyrights goes to the name.
As you are not using any method to steal the actual graphics from the software or the hardware you can create anything.
A circle with a mouth was a great idea for the hardware of the 80's also a triangle for a spaceship was the minimmum and the best for asteroids.
You cannot create a circle with a triangle for mouth and call it pac-man... after all the copyrights goes to the name.