Google X - or Google [x] as the internet search company would have it - is what it calls its "moonshot factory", where inventors and engineers are encouraged to collaborate on audacious ideas.

The X in Google X means 10 - making a problem 10 times better, with a timeframe of about 10 years.

Staff are encouraged to think of "science fiction-sounding solutions" and are rewarded even if they fail, as "Captain of Moonshots" Astro Teller tells BBC Newsnight's technology editor David Grossman.