> actually Of course it was, but the expression stands because of the opacity implied by 'black'. The [original] box contains secrets - it may even be rigged -

> actually Of course it was, but the expression stands because of the opacity implied by 'black'. The [original] box contains secrets - it may even be rigged -, or anyway very complex technology, state of the art, just developed or evolved, especially difficult to understand - you do not know how it works. It is black, and that "black" is significant in many ways. (And of course, a "flight recorder" is not the same thing: it is a specific function - not of the most esoteric - of the original pack of potential embedded technologies, which inherited the name. The radar, for example, becomes "mainstream", while the recorder remains "boxed" because you want it protected for "emergential witnessing".)