While it is possible that Greece (and other PIIGS) remain in the EMU, it's also possible that they leave it. So I'm wondering how would this work in practice? For example, if Greece were to leave, presumably they would go back to the Drachma. However this wouldn't happen overnight for various reasons, including but not limited to printing and producing paper notes and coins. Apart from the multi-year changeover to the Euro in the late 1990s and early 2000s, are there any other precedents for a massive change in currency, particularly where it happened quickly? How do you think it would work if Greece or another PIIGS left the Euro?