A parade of seashells and a deck of cards add up to one thing: a love for a grandchild

A line of carefully placed seashells curves through the living room. It snakes around the coffee table and skirts a lamp. A conch shell the color of a sunrise lies next to a rough oyster shell. There are tiny cones, hinged clams, and shells of various shapes and sizes in this parade.

"Here's a bivalve," says a young voice from behind the armchair, where the shells disappear.

"OK," says an older voice, pragmatic and focused. "Let's take a look."

And so it was that my 3-year-old son learned to identify shells. He'd sit with his grandfather every Friday afternoon, pulling treasures from a large glass jar, while his grandfather, propped on an elbow on the floor, leafed through a field guide.

"Which do you think it is?" my father-in-law would ask, holding the book open, pointing to several varieties.

"Well," my son would consider thoughtfully, "it doesn't have ridges."

"No."

"And it isn't speckled."

"No."

"So I think it must be that one! What's it called?" my son would ask, and then repeat the name, all serious, as he placed it carefully in line.

I grew up in a hurried family and married into a patient one. My children would never have learned such patience from me. When my son paused during toilet training to wonder at a flush, it never occurred to me to remove the top of the tank and let him see what was happening. But this was part of his routine with my father-in-law.

They talked about plumbing (and went into the basement to check it out). They talked about the well. They even, if you can imagine this, stopped by the water-treatment plant. ("This is where the flushed water goes!")

When my son peered, mouth open wide, into the mirror and asked what that thing was at the top of his throat, I was too busy checking items off a to-do list – wash hands, check – to think of looking it up. (It was, as my son told his doctor at an annual checkup, the "uvula." Who knew?)

What makes a boy love his grandfather? Is it the ice cream in the summer or the leaf piles in the fall? Is it the sledding in the winter, the terrarium in the spring, or the trips to the park and the aquarium?

Could it be because of the trips to the boy's favorite place – the natural history museum – where together they pore over drawers full of insects for hours on end?

My grandfather never took me to a museum, and he never read me a book, but he'd lie propped on the ground with a deck of cards and deal them again and again and again. I didn't play with skill or strategy, but it didn't seem to matter.

Years later, playing cards with my own children, I wondered how he could do it – how he could play as though I were a worthy partner when I barely understood the game.

As I watched my father-in-law with my young son, I began to understand.

To my son, every shell was a wonder. And to his grandfather, there was nothing more important for a few hours each week than his grandson's learning the name of the shells that rested in his smooth palm: this Atlantic turkey-wing seashell with its ragged stripes, that cowrie shell gleaming with brown spots.

There was all the time in the world for such a worthy pursuit.

This December the shell-loving boy will turn 14. There's a shadow on his upper lip, and he's as tall as I am. Soon he'll be as tall as his grandfather.

"Do you think he'd like to come down for the weekend?" asks his grandfather. "He's getting to that age where maybe he'd rather be with his friends."

Not yet. Thank goodness, not yet.