GUAC-LOCK: Two best friends were living the good life in Scarsdale, New York. Not good enough! Seeking a challenge, they took on America’s great party problem: how to stop guacamole from turning brown. What followed was a four-year saga to make a container called the Guac-Lock. How two women who’d never made anything before learned about manufacturing—and remanufacturing—and the importance of asking for help.