I think the poster meant off-by-one doesn’t simply mean a plus or minus one error, like mispricing a $5.99 as $6.99, but instead must be born out of confusion as to whether an origin point is marked as a 1 or as a 0.
>I agree subtracting or adding one to any number is not the problem. It has to do with counting.
if you are sprint climbing and you put your hand out to grab and you add or subtract the number 1 from where your hand needs to be, it is a problem or contributes to a speed difference.
Perhaps the pieces are placed by counting a number of holes from piece A to piece B? That's a perfect recipe for an off-by-one: at which point relative to piece A do you start counting.
