I had previously thought of the similar idea, making diagrams similar to the ones in that article.
The article does not mention "debit" and "credit", although that is what they are doing; the arrows point toward the debit side, and they are using the convention of debits being positive and credits being negative. (Since the sales amount is a credit amount and the amount of money you have is a debit amount, so the sales amount appears negative due to this.)
The article does not mention "debit" and "credit", although that is what they are doing; the arrows point toward the debit side, and they are using the convention of debits being positive and credits being negative. (Since the sales amount is a credit amount and the amount of money you have is a debit amount, so the sales amount appears negative due to this.)