Keep in mind also that the 10% reserve doesn't mean physical money (paper/coins). When a bank loans money, it can create $9 out of thin air for every real $1 it holds (be it in paper or in DB entry). When loans are being paid back, the banks count that payment as "real" money against which they can loan 9x the value again. In theory at least, this process can repeat to infinity.
I wonder if anybody unit tested this design for flaws.
I wonder if anybody unit tested this design for flaws.