P . . . is for Periwinkles

 Periwinkles 

 I live on the coast of Maine. We have beaches, but they aren't the white sandy kind that you see in the Caribbean. Our beaches are mostly rocks. In the few places where it is smooth, you might see little wiggly trails through the damp sand. These are periwinkle trails.

 

 Periwinkles are edible, like clams or scallops, but you either have to crush the shell or pick out the meat with a toothpick. It takes a bucketful full of them and a lot of work to make a meal.

 I'd rather just look at them. Periwinkles are round mollusks that range between 1/2 in. to an inch in diameter. Like most mollusks, they have a muscular foot which they pull into their shell when they are disturbed. They seal themselves in with hard fingernail-type door.
.

Each one has his own style. They sport stripes and spots of brown, yellow, or sometimes green or red. I haven't tested my theory, but I think it would very hard to find two that were exactly the same.

 The next time you come to Maine 

and it's low tide, 

let's go 'winkling.