In the hourglass brown fine-grained sand is runninng slowly from the top to the bottom through narrow part of clear figure. Both of the measuring bottles are identical, although looks like the lower is smaller.

Stock photo: In the hourglass brown fine-grained sand is runninng slowly from the top to the bottom through narrow part of clear figure. Both of the measuring bottles are identical, although looks like the lower is smaller. was taken by pirjotti .