Sir Martin Sorrell, the chief executive of advertising giant WPP, today backed the theory that the world economy is about to experience a LUV-shaped recovery. This consists of an L-shaped recovery for western Europe, a U-shaped one for North America and a V-shaped one for Brazil, Russia, India, China and the "next 11" emerging economies.

The LUV theory appears to have first been coined by Stella Dawson of Thomson Reuters. Sorrell himself has a habit of contributing to the economic lexicon - the advertising magnate is responsible for the concept of both the bathtub and the italic L. Other unusual metaphors that have popped up to describe different ways in which countries can emerge from an economic slump including saxophone and inverted square root.

L shape

A protracted period of economic stagnation bordering on depression. Examples include Japan in the 1990s and the Great Depression of the 1930s. Sorrell previously described the current slump as an italic L shape, implying a slow and protracted recovery.

U shape

A feebler and longer recovery than a V shape. Economist Nouriel Roubini warned in October the recovery would be more U-shaped than V-shaped. "I don't know how people can say this is going to be a rapid recovery," he said. "I don't see the argument for it."

V shape

A short recession then a strong rebound. An example is the UK in the early 90s. Alistair Darling was optimistic in July the same could happen this time: "There clearly has been a very sharp V ... but I am confident the economy will start to grow by the end of the year."

W shape

In a W shape or double-dip downturn, the economy returns to growth for a few quarters before worsening again, followed by eventual recovery. For example, in the early 80s slump the US economy plunged into recession in 1980, returned to growth in early 1981 but then dipped again in the same year. America's Great Depression in the 1930s was arguably an L shape followed by a W - but has also been described as a '2.0 shovel'.

Saxophone

This scenario sees GDP going up, then sharply down and back up before levelling off. Accountants BDO Stoy Hayward predicted the UK will suffer this fate, with the recovery tailing off disappointingly quickly in 2010.

Bathtub

Sorrell coined this term in describing the 2001 downturn triggered by the bursting of the tech bubble. "We are now at the bottom of the bath," he said in 2001. Following further volatility, he later decreed that the bath had a "corrugated" bottom.

Inverted square root

Finally, billionaire investor George Soros came up with the "inverted square root". "You hit bottom and you automatically rebound some, but then you don't come out of it in a V-shape recovery or anything like that," he has said. "You settle down - step down."

All you need is LUV?

Sorrell said today: "A LUV-shaped world economic recovery seems the most acute description in the alphabet soup debate on the shape of the current economic cycle. Stella Dawson, Treasury correspondent of Thomson Reuters, points to an L-shaped recovery for Western Europe, a U-shaped one for North America and a V-shaped one for the BRICs and Next 11 [emerging nations]."