Happy World Toilet Day! Flushing toilets can consume a lot of water, so Tak-Sing Wong, a biomedical engineer at Penn State University, is trying to minimize how much is needed. Wong developed a slippery coating for the inside of a toilet bowl. It can potentially move human waste more efficiently, leaving a cleaner bowl and using less water. Follow host Maddie Sofia on Twitter @maddie_sofia. Email the show at shortwave@npr.org.