5 pin bowling balls
Five-pin bowling balls are small enough to fit in the hand, so they do not have finger holes.
So, as it turns out, before the virtual bowling alley borrowed something from the trackball, the inventors of the trackball borrowed something from the actual bowling alley — specifically, the Canadian variation of it, called 5-pin bowling.

Unlike the giant hulking rocks that tend to get thrown in American bowling alleys, 5-pin relies on a ball slightly less than 5 inches in diameter — larger than a skee-ball (which is 3 inches in diameter) and roughly the size of the ball used in duckpin bowling, but using five pins, instead of 10 (hence the name).

Clearly, this is a fairly novel point about an object that has inspired a lot of other devices that have come since — and its one that hints at its initial creation in the early 1950s. The device is Canadian through and through, a project formulated at the behest of the Royal Canadian Navy by Ferranti Canada, as part of a much larger project — a military information system called Digital Automated Tracking and Resolving, or DATAR.

DATAR represented perhaps one of the most ambitious projects of the budding Canadian computer industry at the time, a sophisticated machine that allowed ships to transfer radar and sonar data with one another. The machine was conceived by Navy researcher Jim Belyea, who took advantage of a failed meeting between Ferranti and the Navy to pitch his ambitious idea. According to a 1994 IEEE article, Ferranti was extremely impressed by Belyea's vision.

"It seemed to our group that what [Belyea] had in mind was very much the proper thing to be doing," the company's Kenyon Taylor said. "It was a first step in push-button warfare. Lt. Belyea was thinking 15 years ahead of his time and Sir Vincent de Ferranti and the rest of our party were well in tune with him."

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