Today I write from the New Jersey turnpike, a rider on the highway instead of a walker in the suburbs. That I can do such a thing amazes me. So I write with a grateful heart on a bouncy laptop.

Yesterday I visited Central Park, and when I started strolling uptown I felt both wired and slow; I wanted to move more quickly. I wanted to ride a bike. There’s quite a brisk bicycle-rental business now at the 59th Street entrance and soon I was pedaling around the big park loop: zooming past the boat basin and the Met on the east side, up a small hill to Harlem at the north end, then past a noisy blue swimming pool.

I dismounted at the reservoir, which was my running track when I lived on the Upper West Side many years ago. There were the familiar curves in the path, the lapping water, the St. Remo Towers looming above it all. Coming back on the bridle path under an ornate metal bridge, I thought about the many times I’d walked around that large pond, how much my life had changed since then, but how the pond was still there, more or less the same.

It was early afternoon on a fine hot summer day, and I was back in Manhattan. Right then, that was enough for me.