And they fell briefly at the end of 1998 and 2001, only to rise again strongly.

ECONOMIST: Property prices

"American Chopper" has changed networks, switched names and was previously canceled, only to rise again.

CNN: 'American Chopper' ending after 10 years

The wave diminishes over long historical periods, only to rise again when something truly important is at stake.

NEWYORKER: Slaughterhouse

And we have seen other periods in Iraq's war where we've seen violent levels decrease only to rise up again.

NPR: The Week in Iraq

What is it about the economic recovery so far that allows good news to last for only six months at a time before fears rise again, and the economy needs another adrenaline fix from the Fed?

FORBES: Fear Creeps Back Into Stocks Like Clockwork

And so Tam's only hedge is to keep scavenging for even more paper, shuffling along the city's streets and hoping that prices rise again.

CNN: European slowdown hits Hong Kong's paper paupers