"KISS is commonly expanded as Keep It Simple, Stupid and was a favorite maxim of Lockheed engineer Kelly Johnson."
Publication date from Lockheed Martin article “Kelly Johnson: Architect of Air” (October 1, 2020). + Lockheed Martin explicitly identifies KISS in this form as Johnson's favorite maxim, showing that the principle predates its widespread use in software. + Publication date from Lockheed Martin article “Kelly Johnson: Architect of Air” (October 1, 2020).
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