[IBM] 1. Apparently random flashing
streaks on the face of 3278-9 terminals while a new symbol set is
being downloaded. This hardware bug was left deliberately unfixed,
as some genius within IBM suggested it would let the user know that
`something is happening'. That, it certainly does. Later
microprocessor-driven IBM color graphics displays were actually
programmed to produce green lightning! 2. [proposed] Any
bug perverted into an alleged feature by adroit rationalization or
marketing. "Motorola calls the CISC cruft in the 88000
architecture `compatibility logic', but I call it green
lightning". See also feature (sense 6).