During my recent summer vacation on the Cape, I was confronted with the need to do something with my mind. In essence, I cheated the entire purpose of my beach-relaxation exercise to engage in a quest for the primary equation of visual space: circle, triangle, square. "Circle, triangle, square." I repeated this to myself while sifting through the sand for stones that fit into this geometric order.

• The circle never rests. It is free to go anywhere it pleases. Its continuous smoothness makes it a gentle form.
• The triangle is entirely awkward. It sits firmly on its base, but instills fear with its sharp points.
• The square is the king of bland. Nothing can disturb its purity of shape. It can cause no harm.

Circle, triangle, square. I found 100 triplets on the beach (and left them there, of course). How many can you find on your next vacation?