>so vague that they accidentally copied them? // No, but you're on the right track. Copyright covers copying, if you didn't copy and can prove it then that's

>so vague that they accidentally copied them? // No, but you're on the right track. Copyright covers copying, if you didn't copy and can prove it then that's an absolute defence (see eg WIPO PROOF). Copyright being a tort, the usual measure of proof is 'balance of probabilities'. That means if you didn't copy, but you _cannot_ prove you didn't, and it looks like you probably did, then a court can find against you. There is also the notion of distinctiveness, generic, non-creative things don't acquire copyright ("common elements"; trademark has similar aspects, it's hard to word things without confusing the two, they're differently concepts with the same names). However, in 2012 there was a case in UK law over an image of a London bus, where a re-creation of the image was used commercially. The copyright in the original photo was considered to be infringed despite the image being highly generic (Temple Island V New English Teas, 2012). A lot of people, myself included, are not convinced of this decision (see also Kenrick V Lawrence). USC and UK law differ, but as copyright is based on international treaties such as Berne Convention and TRIPS you find they're broadly analogous in a lot of ways; I can't comment on where the line lies in USA law. This is my personal opinion, unrelated to my employment; this is not legal advice.