There are 4 stages, one for every currency. In stage 1, a 20 dollars bill need to be revealed. Right of the blank bill, there are 3 symbols, which represent the dollar. And under the bill there are all random symbols, which will switch from time to time. Click only the symbols, which represent the dollar to reveal the whole bill.
In the rest 3 stages, the same is done for the yen, the pound and the euro.