Social media and news channels were saturated yesterday (3.14) with Pi Day posts to celebrate the magical number, but we’re savoring ours today.

A few years back we posted a photo of the Pi-Alley sign in Wellesley off of Washington St., in Wellesley Hills as our version of a Happy Pi Day message. But I realized yesterday I had no rational idea why P-Alley it was actually called that.

I couldn’t find it listed on the official town street list, and the town’s chief assessor confirmed that no properties are officially located on it.

A little online investigation turned up a short history of Pi Alley in downtown Boston from the Pi Alley Garage: “In the days that Washington Street was home to most of the city’s newspaper printing plants, many of the printers and typesetters frequented a tavern in the alley called the ‘Bell in the Hand.’ In their haste to get refreshments, newspapermen would often drop pocketfuls of mixed up, loose type (called ‘pi’ in the printing business) on the ground, leading to the name ‘Pi Alley.'”

Bringing things back to Wellesley, that association with printers made sense for Wellesley’s Pi-Alley, too.

Pi-Alley here abuts the DeFazio Building, the 1890’s structure that sits across the street from the Wellesley Hills train station. Among the building’s tenants is The Windsor Press, which has been in the printing business since 1929.

Windsor’s Tory DeFazio tells us:

“Yesterday was national PI day, so I got some greetings, and explained to folks the origin of PI from a printer’s perspective. PI Alley was the entrance to where my office use to be (360 Washington St.)—down the alley on the left where the wall sign is. The alley is on my property. I had to have some way for people to know how to come in, so I came up with the catchy ‘PI Alley.’ It worked.”

DeFazio adds: “Then we were fortunate to move back to 356 many years ago where we are today. We’re in a better position now!”