The landscape of the pagodas is featured on the 1-yuan note. [Photo provided to China Daily]

The real answer lies in the three pagodas, which imperceptibly divide the water into three parts.

Again, ignore your scientific mind. Call up your inner poet.

As each pagoda lights up a limited area around it, the vastness of the unlit water is simply discounted, rendering it into three pools.

Well, this is just one justification, but it is as good as another.

If you don't believe me, just whip out your wallet and look at the back of a 1-yuan note.

It features a daylight scene of the three familiar pagodas. But given the angle of the picture, the distant pagoda could not possibly be there. Call it artistic license, which, if you think of it, is not that different from a perspective-free scroll painting.

The pagodas were built by Song Dynasty (960-1279) poet and governor Su Shi, who was also responsible for the Su Causeway on the lake.

He meant them to be watermarks to gauge the necessity of dredging of the lake. They were rebuilt in the Ming Dynasty (1368-1644), and the nearby islet was constructed from silt and mud in 1607, with improvements and architectural additions later.

Meanwhile, the origin of the structures being known has not prevented people from coming up with their own versions, many of which involve a snake-headed demon.

Unlike the famous White Snake spirit, this fish demon is a villain who snatches local girls or thrashes the city with storms.