Despite its memorable showcasing in the Terminator films as a useful aid to the annihilation of humans, the heads-up display (or HUD, or computer you wear on your face) could have more benign applications.
Google was keen to stress these yesterday as it unveiled "Project Glass", an HUD that will – if it ever comes to market – be able to show you weather forecasts, proximity of friends, calendars and much else besides; essentially a smartphone, but plonked in front of your eyes and controlled with a tilt of the head.
Having icons in your line of sight, like pieces of digital debris floating in your vitreous jelly, could become annoying, but Twitter's @tomscott produced a spoof Project Glass video that summed up a greater Google-related concern: a full-screen ad for a carpet warehouse unexpectedly springs up, obscuring his vision and causing him to fall over as he shouts: "Cancel! Cancel!" Hasta la vista. Maybe.