Again, Nilay Patel at The Verge (maybe read the article? http://theverge.com/2011/04/19/apple-sues-samsung-analysis/):

Trade dress law is well-established, and Apple itself has a history of successfully pursuing trade dress claims in the Northern District of California. In 2000 the company sued both eMachines and a company called Future Power for knocking off the iMac's trade dress, winning injunctions in both cases and eventually getting extremely restrictive settlements that effectively removed the infringing products from the marketplace.

The eOne: http://lowendmac.com/imac/eone.shtml

Article about the case: http://zdnetasia.com/apple-stops-sales-of-imac-knockoffs-130...

The 2011 case featured in the Verge bundles trade dress claims, that have been enforced in the past with a less simple and much more distinctive look, with design patents, which I'm not aware Apple has been able to enforce before. The other one we discussed is for a European “community design”, something which was created (sorry, “harmonised”) in 2002, and those extremely simple shapes were registered by Apple in 2010: http://www.scribd.com/doc/61944044/Community-Design-00018160...

Here is what makes community designs a step up from other roadblocks against competitors: http://www.osnews.com/story/25056/The_Community_Design_and_y...

If by 'new' you mean 1946 then sure: http://en.wikipedia.org/wiki/Lanham_Act

That's trademarks, which so far have been more faithful to their stated goal of preventing consumer confusion, rather than creating new kinds of private property. For example, I don't need Apple's permission to use the trademarked word Apple, as long as I'm referring to the firm, or as long as I'm not using it in the context of electronics or music.