Frothy mass visible on plant stem hides curious bug
The concept itself can be identified as far back as Sun Tzu's 'The Art of War,' although he didn't use the term. It purportedly stemmed from WWI aviators. But it was air crew members fighting in Korea and Vietnam who are mainly given credit for mainstreaming the short phrase. The idea has gained some spread, having been popularized by human factors scientists more than a decade ago.