In March 1988, technical middle managers at Apple held an offsite meeting to plan the future course of Mac OS development. Ideas were written on index cards; features that seemed simple enough to implement in the short term (like adding color to the user interface) were written on blue cards; longer-term goals—such as preemptive multitasking—were on pink cards; and long-range ideas like an object-oriented file system were on red cards. Development of the ideas contained on the blue and pink cards was to proceed in parallel, and at first, the two projects were known simply as "blue" and "pink". Apple intended to have the "blue" team (who came to call themselves the "Blue Meanies" after characters in the film "Yellow Submarine") release an updated version of the existing Macintosh operating system in the 1990–1991 timeframe, and the Pink team to release an all-new OS around 1993.