hello…
i’m by no means a copyright expert or lawyer, but copyright in the u.s. is granted to the original person by default (e.g. you don’t have to apply for it, really), and in theory a design like this could be copyrighted…however, in this case (the pencil effect), it might be too generic to copyright as a concept, and at most the company that did it first could send a few threatening letters to the other that ask them to alter their design, but it would seem in this case that it’s more of a copycat than a copyright…
that said, you could of course put a copyright symbol on your site’s design and then you have (for all intents and purposes) “copyrighted” your art, but with millions and millions of web sites out there, how would you ever know if somebody stole your idea? and if they weren’t in the same country as you, what are your options? in theory other countries have to honor your copyright claim, but if you’re in the u.s. and somebody in (for example) brazil steals your idea and uses it and refuses to answer your requests to stop using your idea (assuming you found them in the first place), then what would you do? take them to court in brazil? not very feasible, unfortunately… 🙁
so the best thing you can do is just do what you want on your site and put your copyright on there, but if it’s a good enough idea and your site is popular enough, then it’s a matter of time before someone uses your idea on their site and alas there’s not a lot you can do, really, outside of those standard cease-and-desist letters…
hope that helps!
sitruc