In the details or can you believe that this is a storm grate?

I've been going through some of photos I took back in 2009 and thought that this photo was interesting. I've always found that the Japanese are especially good at the small details that make even the most mundane of things interesting. This stormdrain grating in Setagaya near Baji Koen had an unusual pattern. Not sure if it is a bunch of boys kicking balls or a boys kicking other boys heads. The repetitive pattern or tessellation is very Escheresque.

Nikon D700with Nikon 50mm f/1.4G AF-Sf8, ISO 400, 1/50 sec.