During the Tang dynasty (around the 9th Century CE), traveling intellectual Li Yuanming would routinely leave home to write and debate poetry with likeminded scholars across China, isolating his wife Cifu for sometimes weeks on end. Frustrated, she found comfort in the arms of a widowed neighbor, but when Li remained at home for an unexpected stretch of time, Cifu was prompted to develop a method to signal her lover it was safe to approach. She stitched a special green hat that she handed to her husband as he was about to leave town; when Li was wearing the hat, it worked like a traffic signal - green meant go. But this didn't last for long, during one trip Li returned home early and caught Cifu and their neighbor together, and when the local ... read more