Seeing (and valuing) what is not

Have you ever thought of noticing and appreciating what is absent? I just found a little article on this principle and here's an illustration offered:

Many of the things we use are examples of the value of nothing. Claw hammers remove nails with little effort using a simple tool, a split in the metal. The opening -- where nothing is -- creates the function of this part. Without the space, it's a dull chisel.

Here's another short excerpt:

Between every event, every moment, every action and every reaction, there is a place to pause and think. Sometimes the pause is very brief, even just a moment. But a moment is a moment.

Look for the moments when there is no sound, no movement. Look at the still walls, the still ceiling, the stable trees or placid grass.

I really like the idea of looking for what is not there - not seeing that as deprivation but, rather, seeing the basic value of the absence of some things.