B6 is using a fin to tell time

This odd bit of artwork had confused us for some time. What is it? Is it a whale, or fish or something? A weird plaground with nothing on which to actually play?
It is the Marulan Meridian Arch and the accompanying sign tells us:

The arch marks the path of 150th Meridian as it passes through Marulan, the only town in the world on its path. This is the exact middle of the Eastern timezone where the sun rises at exactly 6am and sets at exactly 6pm every equinox.

Now, this is the good bit,

"The sculpture describes the path of the Earth around the sun, while the two elements at each end of the structure represent a sun dial and a clock."

So B6 is actually showing you the time on the sundial. Or Fin. Or whatever.