They look better if you paint them with a roller. "Sand" kind of fades into the background. You c an smooth the surface somewhat by rubbing two blocks against each other, or rubbing them with a brick. Then you have to wash the dust off before painting.
Hiding the holes with some kind of top cover (like a paving stone) also makes them look better. That also makes it easier to set things down on them.
I think it would take a triple row before they were high enough to sit on!
Someone planted trailing things like lobelia or alyssum in the holes, and they hide the blocks a little.
