One person has bought and filled a canister with sugar. Another person starts using that sugar. When the sugar supply gets low, the supplier tells the borrower, they will have to replace what they have used. The borrower agrees to do this. The supplier fills the canister with the sugar remaining in the 4 pound bag in the kitchen cabinet, which now has 1/4 sugar. Then supplier is uncertain about the amount of sugar in the canister. It’s not filled to the top, but it’s not empty, either. In fact, the supplier cannot remember how much sugar is in the canister. And has already forgotten that the bag is no longer in the cabinet, but in the garbage.
One morning, concerned that the vital sugar supply to sweeten the daily mug of espresso is dangerously, the supplier checks the cabinet and discovers the bag is no longer in there. Feeling threatened, the supplier moves the canister from the kitchen to a safe place.
The borrower bangs on the supplier’s door the next morning, waking up the supplier, angry and upset, that there is no sugar in the kitchen.
(BORROWER) Where’s the sugar!
(SUPPLIER) The supply was dangerously low, so I moved the canister.
(BORROWER) But I replaced what I had borrowed!
(SUPPLIER) When you have replaced what you have borrowed and continue borrowing from the same pot, then you have not replaced what you have borrowed.