Mysterious bumps and holes.  Air holes?  Igloos of little sand creatures?  Nothing seems to be under them, but there they are.  Lots and lots of holes, many fewer bumps.  The holes are less than 1/8″, the bumps perhaps 1/2″ wide and 1/4″ high.  Perfect little mounds.  Soft.  Nothing visible inside them.

Knock, knock.

It’s very had to know who is there.