"The Knight is on D1." and "The Knight is at D1."
Semantically the sentences mean the same thing. They are describing the position of a knight on a chessboard. The document I am writing contains a lot of these examples. They describe a valid scenario of a chess-style game which will be parsed by a computer program.
Given the game has just started
And the Pawn is on E2
And the Knight is at G8
When I move the Pawn to E4
Then I should be shown "Pawn to E4"
And the Pawn should be at E4
I have found myself changing between 'on' and 'at' for what I think is a variation for the sake of readability and to keep the reader engaged. Linguistically, how you describe this variation? Is there an academic term for it? And is there an academic term for keeping the sentences exactly the same?
Note: I am not asking for which style is better or worse. I just want to write about what the difference is. How I would describe it.