"the need for the "line-for-line" copying of just the API declarations was the bare minimum needed for interoperability in the world of software."

I would argue that the use of the Goldsmith art to create the silk screens was needed for the "interoperability" of the statement warhol was trying to make.

The fact that it IS specific, recognizable art is what makes the actual mental connection, a sort of "API of the psyche", if you will, and hopefully conveys the desired information to the endpoint, or viewer.