Sand Dudes Play Chess

This photo's EXIF data points to El Cerro, Puerto Vallarta, Jalisco, Mexico. So what is that, anyway, a sand sculpture?

Chess players © Flickr user re_p_g_c under Creative Commons.

A different Flickr photo of a similar subject (with better lighting), signed Arnie Rose, tells us,

At first glance, I thought this was a very impressive sand sculpture, but then the figures moved, ever-so-slightly. The entire set is covered in a sand finish and the two "actors" are also covered in a sand-based make-up of some sort.

The box on the ground is for 'Tips'. Knights before Bishops?