I have believed for a long time that this idea of the gold coins/money is very doable.
Even if we keep the existing system of currency notes what can be done is as follows;
We all know that each currency note has a mettalic wire in it which is easily visible on holding the note up against light. If we simply replace that wire with a gold wire which is equivalent to the value of the currency note this way we do not have to carry coins and still can carry currency notes that are easier and we are used to.
This same method can be used to pay with debit cards and credit cards if we disregard the interest on the credit cards for that is also not that hard to solve but only for the bankers and legalised loansharks.
Will appreciate comments on the idea.
