The Latest Wrinkle in Crumple Theory From studies of “geometric frustration,” scientists learn how paper folds under pressure. In a sense, creases happen when a thin sheet of material gets claustrophobia. “The sheet is stressed, so something needs to happen to relieve that stress,” said Jovana Andrejević, a Ph.D. student in applied physics at Harvard.Credit...Jens Mortensen for The New York Times By Siobhan Roberts March 8, 2021 A piece of crumpled paper, in all of its creased fragmentations, suffers from “geometric frustration.” Who among us can’t sympathize? In a sense, creases happen when a thin sheet of material gets claustrophobia. “New creases form if a sheet doesn’t comfortably fit into its confined area,” said Jovana Andrejević, a Ph.D. student in applied physics at Harvard and the lead author of a new paper detailing the latest advances in paper crumpling.