Here's a brief excerpt:

"Design patent secures for their owner a fourteen-year right to exclude others from making, using, selling or importing the claimed product and, thus, allows time to build up secondary meaning necessary to acquire product design trade dress protection. Trade dress protection can last for as long as product design trade dress remains in use and continues to identify the source of goods to consumers. "

And other one on infringement:

"Infringement of the design patent is found when an ordinary observer, giving the attention of a purchaser, perceives the patented and the accused designs as substantially the same, in light of the prior art."

In the court opinions on Gorham v White (1871):

"It is not essential to identity of design that the appearance should be the same to the eye of an expert. If, in the eye of an ordinary observer, giving such attention as a purchaser usually gives, two designs are substantially the same -- if the resemblance is such as to deceive such an observer and sufficient to induce him to purchase one supposing it to be the other -- the one first patented is infringed by the other."

This is why if Samsung creates a product whose design is substantially similar to Apple's, then infringement may occur. This is why the jury consists of "ordinary" people who are the right people to make the judgement call. Too many HN readers are complaining that the jurors should be technically minded because they are thinking of utility patents, and not design patents. You also fall in the same boat, but I'm guessing most HN readers don't even realize there is such thing as "design patents" and "trade dress protection". This is why lawyers are paid to do the arguing, while we sit back and yell from the sidelines.