This is a repost from another exchange.
I was going to write a paper about code to rotate elements in an array, but I realized I have no idea why rotation towards the start of the array is “left” and “right” goes towards the end. I’ve seen horizontal tape diagrams of arrays, with elements going left-to-right (i.e. Western-culture reading order), but I don’t know if that’s the actual reason.
Maybe finding out who first came up with the convention would help.