(Title with apologies to Simon & Garfunkel…)
As I was working on a little post Christmas reno project, I vaguely remembered that one of those shapes on the screwdriver had a background that was Canadian. I was thinking it was the Robertson, but I had to Google it to be sure and also to be sure that this was indeed the square one (since we girls call these shapes by their REAL names: flat, star and square).
Mr. Robertson’s shape received a Canadian patent in 1909 and he began producing the screws in Ontario shortly thereafter. (His drawing is shown here: https://en.wikipedia.org/wiki/P._L._Robertson)
Evidently, he was not the first to think of the shape (there is an American patent) but was the first to find the answer to the manufacturing end of things. So the shape to this day bears his name, even though I shall always lovingly call it “the square one”.