Seiko Epson Corp. sued Nu-Kote International, alleging that Nu-Kote had infringed on its design patent for ink cartridges for printers. The district court held that Seiko Epson's design patent was invalid because: (l) the cartridge is not visible after its installation and during use and thus its design was not a matter of concern to consumers," and (2) the design is not aesthetically pleasing. Is the district court's reasoning correct? What are the requirements for a valid design patent