Clemens Franek (defendant) designed and manufactured a circular beach towel. Franek advertised his round beach towel as being both: (1) a fashion statement and (2) a way for sunbathers to reposition themselves with the movement of the sun without the hassle of having to move their towels. Franek trademarked his round towel with the Patent and Trademark Office. Although Franek held a trademark for the round beach towel, other parties held patents for round beach towels. One of these patents described, in its claims, a towel of circular shape that allowed a sunbather to “reposition his or her body towards the changing angle of the sun while the towel remains stationary.” Twenty years later, Franek learned that Jay Franco & Sons, Inc. (Jay Franco) (plaintiff) was selling round beach towels. Franek sued two retailers of Jay Franco’s round towels, Target and Walmart, for trademark infringement. Jay Franco then sued Franek, seeking a declaratory judgment that Franek’s trademark was invalid. The district court held that Franek’s trademarked design was functional, making the design ineligible for trademark protection. The district court invalidated Franek’s trademark and granted summary judgment for Jay Franco. Franek appealed.