Is it sand, ice, a landscape, bird shit, a glacier, a frozen lake or a river delta?

It´s black and white colour (varnish) painted on a stone and a very small sector of just a few centimeters of it.
Thanks to Sven Hessler for creating this piece of Art!

Helgoland, May 2020

Canon EOS 90D  |  Canon 100 mm  f/2.8 L Macro |  1/1600 s  |  f 4.5  |  ISO 160