This expression, most likely alluding on the idea of pie as anything sweet and attractive, and sky as during the air, beyond one particular’s reach, was popularized in a Globe War I track generally attributed to Joe Hill (1927): This developed the illusory effect of reversed localization of sound. https://bookmark-template.com/story24224573/the-5-second-trick-for-illusion-of-kundun-mu-online