Some people are seriously considering what if the eurozone broke up. If some countries are departing eurozone abruptly, they don’t have time to produce new currency. It would need to find temporary ways to separate its share of the euros from the rest. One people suggested laser engraving.

… it to laser-engrave distinguishing marks onto the portion of the euros, which would have been allocated to the country departing the eurozone. This can be done relatively quickly and would make the currencies irreversibly different, said Mathes, adding “but I suspect that the European Central Bank will not look kindly on a state burning holes in its currency.

That would be good for laser companies in the crisis.

via Centre for European Reform: What if the eurozone broke up?.