No sooner had I photographed the rather satisfying mark left on the back lawn by our paddling pool than I opened the mailbox to find an invitation to the latest exhibition at Jonathan Smart Gallery, also on a circular theme.

Surrendering to the magnetic pull of synchronicity, I had a quick rummage through the Gallery's online collection, which yielded the following My Gallery selection (there are, of course, many, many more examples). Note: you have to really want it to be able to see the circles in the Mrkusich painting, but if you press your nose up against the screen, you'll get there.

And if, like me, your grasp of geometry is a tad hazy, check out the jaunty refresher below so you can wow them like it's 1985.