Four Iowa students recently received top marks at the fourth annual Invention Convention U.S. Nationals, held at the Henry Ford Museum of American Innovation in Dearborn, Mich. Charles Smith of Ottumwa won first place in the kindergarten grade category for “Benge Beacon,” which can be used by fire departments to mark exits in residential buildings when firefighters enter a burning building. Eighth grade student team Rebecca Yanacheak, Dylan Hunt and Thomas Nugent of Adel won a patent application provided by the law firm Cooley for “Easy Shuck,” an inexpensive mechanical solution to grip and peel corn.