tetris was not developed for a game platform, it was developed in the soviet union as a side project of a computer scientist in a research lab, and then was traded freely around the soviet block for a few years before it trickled out into the western world and became a commercial commodity. because of its origins in a communist state no one technically owns the copyright for tetris (although nintendo owns the specific iteration they made for nintendo, and the music that they made for it), so there are clones on most home computers, etc. and they can even be called "tetris", and not "block game!" or something.