But running time can be extended by repeatedly winding up the spring and transferring its energy into the battery.

ECONOMIST: MONITOR

Repeatedly winding up the spring and dumping its energy into the battery (a process that takes about two minutes) can increase the total running time.

ECONOMIST: Clockwork technology

The so-called London Whale blunder weighed on shares heavily in the spring and summer, but with the year winding down the stock was just a few bucks shy of its 2012 highs.

FORBES: Bank Of America Doubles, But The Dow's 2012 Gain Is Built By Home Depot