And, indeed, the majority of fast-food restaurants feature red prominently in their colour schemes.

FORBES: Why Picking The Right Color Can Make Or Break A Brand

Even so, it would seem that full colour, fully flexible displays that can switch fast enough to show video are still some way off.

ECONOMIST: REPORTS

T68, with a built-in colour display for better games and graphical messaging, is selling fast.

ECONOMIST: Mobile telephones