Much has been said on this issue and those of us who have spent a lot of time on it before won't necessarily be excited to see it again. Before posting on this topic read the forum and make sure you are adding something new. The site search feature will likely turn up a lot to read and catch up on if you have not been following this topic over the last year or so.
Regarding Rubik's and trademark this has been mentioned before so please look it up and read what has been written already. I don't know enough about the issue to come down with a site policy on it and clearly there is a greater difference of views than for other things considered KO.
I don't have a lot of experience in the area but Wikipedia (here
) says this about trademark in its "Fundamental concepts" section:
The essential function of a trademark is to exclusively identify the commercial source or origin of products or services, such that a trademark, properly called, indicates source or serves as a badge of origin. In other words, trademarks serve to identify a particular business as the source of goods or services.
I think a credible argument could be made that there are a large number of non-Rubik 3x3x3s for which there is no attempted confusion that they originate from Rubik's (i.e. Seven Towns).
I found this
link about a ruling against the trademark, although it was for cubes of different colors. It is informative on the subject, however.
On cubes with the same coloring I would assume the trademark to be stronger. I would also be curious as to how this trademark applies to a DIY where coloring is determined by the builder (although the source colors may be the same).