[pxtail]

Yep, letter S and a number is copyrighted, can't do that

[Biganon]

1) we're talking about trademark law, not copyright law.

2) the problem here is that they're in the same business segment, and explicitly reference S3.

[paulddraper]

S3. But trademark law prevents subtle variations.

E.g. creating a product called “Gooogle”