It takes something special to make hurrying New Yorkers stop in their tracks, but I'll bet guineas to gooseberries they'll halt goggle-eyed when they spot this three-dimensional chalk drawing by British pavement artist Julian Beever on the south side of Union Square.
Makers of a new anti-aging product commissioned Beever, nicknamed the "Pavement Picasso," to create a modern-day Fountain of Youth in the core of the Big Apple.
Painted on the two-D surface of the sidewalk is an incredibly realistic 3D image of a fountain splashing water into a blue pool. An attractive girl is standing in the shrub-lined pool, and at the far end a man is testing the depth of the water with one foot. But it's all a magnificent illusion.
Following Rome's "three coins in a fountain" custom, spectators are invited to toss coins into the fountain and make a wish. For every penny pitched into the "fountain," a donation will be made to the Keep America Beautiful campaign.
Beever began his career creating chalk art to finance his travels around the globe. Based in Britain, he has made pavement drawings for more than 10 years. He has worked in the UK, Belgium, France, the Netherlands, Germany, the USA and Australia, according to his website. He specialises in pavement drawings, wall murals and traditional paintings.
How does he achieve that incredible 3D effect? Vaughan Bell, of Cardiff (Wales) University's School of Psychology, says:
Turning to other visual illusions, Michael Bach's website in Germany claims to have attracted two million hits a day. It shows rotating circles and other colorful patterns which make you dizzy when you look at them.
"These pages demonstrate visual phenomena, called optical illusions or visual illusions," he says. "The latter is more appropriate, because most effects have their basis in the visual pathway, not in the optics of the eye...
"Most visitors of this site are not vision scientists, so you might find the explanatory attempts too highbrow. That is not on purpose, but vision research just is not trivial, like any science. So, if the explanation sounds like rubbish, simply enjoy the phenomenon."
New York's Fountain of Youth is the brainchild of Rohit Bhargava, vice-president of interactive marketing for Ogilvy Public Relations, one of the world's largest global PR agencies. Bhargava, who spent four years in Australia, now lives in Washington DC.
"I am in New York today working on an interesting project for Aveeno where we have commissioned Julian Beever to create a three dimensional pavement painting as part of the skincare brand's support for the social marketing campaign - Keep America Beautiful," he says in his blog. He adds:
If you would like to see a great selection of Beever's mind-boggling art in various cities around the world, take a look at this video.