Another was to use foreign currency: the bank could lend, or accept a bill of exchange, in one currency and collect its debt in another, building a hidden rate of interest into the exchange rate.

That will lead to currency crises and cross-border disputes like the current spat between Iceland, Britain and the Netherlands over the bill for compensating depositors in Icelandic Banks.

We've already seen artists using money to create Cool Dollar Bill Origami, and you've probably already noticed that lately there has been an increase in innovative currency-related artworks.