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I was looking into logical operator diagrams to learn about that stuff and I couldn't find out why the AND operator has a straight base while the OR has a curved one. Does anyone have an answer, or a good link to forward? I suppose maybe it is what it is ? There has to be a reason behind it though.

See below image

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    Don’t overthink this, it’s just a convention, though, it may be based on electrical engineering history/convention. Commented Sep 11, 2024 at 1:10
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    Blame our marketing teams... Just kidding. Seriously though, it's there to provide distinction. You could probably argue why a circle means inversion instead of a triangle or a square. Before these curvy shapes, they used to just be all rectangles with symbols inside of them that signified the logical operation. I would imagine that it created confusion or it was difficult to see so they probably decided to draw something easy yet distinctive. Commented Sep 11, 2024 at 1:16
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    "There has to be a reason behind it though." - Not necessarily. Or that reason could have been trivial (i.e. it looks more aesthetically pleasing) or mundane (i.e. it is easier to distinguish the symbols if some have curved backs) or historic (i.e. what people did in the early 1900's before there were any standards) or all of the above. Commented Sep 11, 2024 at 1:46
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    If you really want to know, start by doing some research into circuit diagram symbology standards from the 1940's and 50's. (But I suspect, that won't tell you "why". For that, you would probably need a time machine.) Commented Sep 11, 2024 at 1:51
  • @StephenC exactly. My answer goes more in-depth to some of those standards from the 60s to 90s and none that I could find provide an actual reason, and simply define the symbols. Commented Sep 11, 2024 at 2:10

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I found a Stack Exchange forum that linked the standardization of these symbols back to 1991 standard IEEE Std 91/91a-1991, which is based on the 1962 MIL-STD-806 Graphical Symbols for Logic Diagrams military standard. MIL-STD-806 doesn't explicitly state why the AND and OR operators are drawn the way they are. It is possible that the reason behind the design of these symbols is not documented at all.

In the question's comments, @StephenC was on-point by mentioning that there doesn't need to be a clear or exact motive behind the design of these symbols. They could be more aesthetically pleasing, practical, or have a historical backing.

On an interesting side-note, (since I understand your goal is to learn more about these logical operator symbols) even after these symbols were standardized in the military in 1962 with MIL-STD-806, it seems that it still took a while to adopt. This is shown with the 1984 standard 91/91a-1984 - IEEE Standard Graphic Symbols for Logic Functions, which prefers a box with a symbol inside:

The distinctive-shape symbol is, according to IEC Publication 617, Part 12, not preferred, but is not considered to be in contradiction to that standard.

Image showing the box-with-a-symbol and the distinctive-shape symbol

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I believe that there would have been earlier standards than that 1962 standard. But logic diagram notation(s) go a lot further back than that. Probably the 1920's or earlier. When digital logic was implemented using electromagnetic relays ...

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