These included how the point of novelty test - which says that plaintiffs in design patent infringement cases must prove that an accused design "appropriate[s] the novelty in the patented device which distinguishes it from the prior art" - should be administered, and what role, if any, claim construction should play in a design patent infringement analysis.

However, Robert Katz of Banner & Witcoff in Washington DC, who attended the hearing, said that the judges focused almost entirely on the first question posed in their en banc order, namely whether or not to scrap the point of novelty test - which many in the design patent community view as inconsistent and confusing - altogether.

The hearing thus transcended the scope of the case in question, which relates to an appeal from a 2003 district court decision that said beauty products company Egyptian Goddess had failed to satisfy its burden to prove that competitor Dror Swisa had infringed its US design patent (number 467,389) for an "ornamental nail buffer" design under the point of novelty test.

Egyptian Goddess appealed the decision to the CAFC, and a majority of the Court affirmed it in August 2007, before granting the order for en banc hearing in November 2007.

Katz, who said that the courtroom was unusually packed for a design patent case, described the judges' questions as "insightful" and "thoughtful". He also said that both parties somewhat struggled to answer many of the questions posed by the full panel.

For example, Katz said that Chief Judge Paul Michel's request for evidence of the ways in which the point of novelty test has failed up to this point, which the judges would need in order to justify discarding the test, proved especially difficult for Egyptian Goddess's counsel to answer.

However, Judge Timothy Dyk, who dissented from the majority opinion in the case, asked questions which gave "the impression that he thought the point of novelty wasn't the right approach", said Katz.

Many amici submitted briefs specifically challenging the Court's new "non-trivial advance" test, outlined in its majority opinion in Egyptian Goddess. In its decision, the Court said: "For a combination of individually known design elements to constitute a point of novelty, the combination must be a non-trivial advance over the prior art."

Nike's amicus brief in support of granting Monday's en banc hearing said: "Egyptian Goddess will force courts and litigants to place focus, in part, on nebulous categorizations of a design's point of novelty as 'trivial' or 'non-trivial', essentially guaranteeing varied and inconsistent point of novelty jurisprudence."

The judges' decision not to address this controversial point during the hearing indicates that they may be seriously considering the larger question of whether the point of novelty test should be abandoned entirely.

"It would be a good sign [for design patentees] if the Court chose to create a more balanced design right," said Katz. He continued: "There might be growing pains at first, but it would be more workable in the end."

A decision in the case is not likely to be issued for several months.