palindromic time piece

One, two, three... these are the numbers normally used to start listing out a quantity of something.

Zero, one, two... these are the numbers I use when I start to count the laps that I run around a track.

-1, 0, 1, 2... This is how I count the train as it pulls in to the station. The train present value is -1 at all times that no train is present, when the engine comes in, that's the zero, and then the train cars themselves are counted in order with one being the first one after the engine.