Most of us have experienced odd coincidences that make us wonder.

My most recent experience with how small the world is involved the column I did about a Glen Park man who found an old football in a heating duct in his home.

He had called to speak to someone in our sports department, but none of the writers or editors, who usually work late shifts, were at their desks.

So he followed the phone system prompt to press 0 to speak to someone in the newsroom immediately. I just happened to pick up the phone.

That column ran on a Sunday. On Monday, one of my writing students at Indiana University Northwest told me that the finder of the football was her stepfather, and the duct in which it was found heated the room in which she slept until she moved out of the house shortly before he called the paper.

But this coincidence is cosmically small change in comparison to something that happened recently in Buffalo, N.Y.

Kevin Stephan, 17, was washing dishes in a restaurant when a customer, Penny Brown, began choking. A volunteer junior firefighter, Kevin stepped up and performed the Heimlich maneuver, according to The Associated Press.

Only when Penny had regained the use of her windpipe did Kevin’s mother recognize her as the nurse who performed CPR on Kevin when he was struck on the chest by a baseball bat in 1999.

As strange as this is — Penny says she can’t think about the incident “without being freaked” by it — such things happen.

Call it the hand of God, a manifestation of “The Force,” or an obscure amendment of the laws of probability, coincidence abounds in a range from the simply odd or the truly bizarre.

A similar tale of reciprocal life-saving occurred in Massachusetts in 1973. Roger Lausier, 13, saw a man struggling in the water off a Salem beach and went into the water to save him.

The man he saved was the husband of Alice Blaise, who had saved Roger from drowning when he was 4.

While you’re hearing that “Twilight Zone” music in your head, here are a couple more well-known classics.

Before filming started for “The Girl from Petrovka,” released in 1974, actor Anthony Hopkins spent a day in London bookstores looking for the George Feifer novel upon which the film was based. After a fruitless search, he headed for the train station, where he found a copy of the book on a bench. Years later, he met Feifer, who identified the find as a copy of the book he had loaned to a friend.

And on the dark side of coincidence lives a Bulgarian woman, an Internet legend, named Martha Martika, whose husband was killed by lightning.

She remarried and her second husband also was killed by lightning.

Perhaps figuring that the third time is the charm, she remarried, but, alas, lightning killed that husband, too.

In a case like that, the superstitious would suspect some kind of a curse.

But even those of us who are dubious when it comes to hexes have to admit that strange things happen.

And all we can do is hope than when the fickle finger of fate points in our direction, it isn’t spouting lightning.