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

It´s the water surface of a small lake with a morroring tree. The slight wind caused small waves, creating this pattern.

For a similar picture with varnish see here: V A R N I S H

Schortens, Friesland, Germanyi, 8 January 2022

Canon EOS R5 |  Canon RF 100-500 mm f 4.5-7.1 L  | 106 mm |  1/320 |  f 9  |  ISO 25600