There is an iron post, about three feet tall and two inches across, that sticks out of the lawn outside my building. I know it is there because I have very nearly taken myself out at the kneecaps on it several times. I don't know what it is, or what it used to be, only that it juts from the grass almost directly in the path that I usually take to cross the lawn.

It disappeared yesterday.

I was walking with my eyes on the ground and suddenly swerved out of habit, just knowing without even seeing it that I was about to run into the thing. But when I looked up to see how close a call it had been, it wasn't there. Later I looked for it from my third-floor window, from which I can usually see it hiding through the pine fronds, and it still eluded me.

It is back again today.

I know because I walked into it.