Poker-chip-size clay coins made by Beriah Wall, a Brooklyn artist.

For more than 30 years now, sharp-eyed New Yorkers have been finding them on ledges, windowsills and store counters — poker-chip-size coins that reveal themselves to be something far more mysterious than loose change.

I found one recently and decided to give it my sister, then I randomly met a woman who had some too and learned where it came from. Now I want more!