Never underestimate young children and just how much they actually do understand about how the world works.
The last item on their (long) list of presents in their letter to Santa this year was written down as a Golden Coin machine. I asked them to tell me more about this toy as I had not seen the advert for a Golden Coin engine on any of the Tv channels they watch (their usual technique is to press the "Pause" button on the digital set-top box in order to pause live television, then fetch me and point to the screen saying "Daddy, please can we have this for Christmas" - any politician promising to ban all adverts on children's tv will get my vote in the next election!).
They considered explained to me that because presents cost lots of money, what they needed was this engine which made gold coins so that they would be able to buy all the other presents they wanted with the money it made. Straightforward really. Can't think why I haven't bought one of these machines myself!
As an aside, it is spirited to note that even at their tender age, they prefer gold coins to paper money (later in life they will learn all about money as a store of value, inflation and fiat currencies). This must be something to do with all the toy paper money and plastic coins they have already played with which does not actually buy anyone in the real world. Interestingly they didn't ask for an Atm engine where they regularly see Daddy taking his cash out of the bank. And they didn't ask for a bank either even though they know (just like the American bank robber Willie Sutton did) "that's where the money is". Maybe even kids can sense that banks have been straight through a rough patch recently and still have structural problems with loan-to-deposit ratios that are too high (there is no money in most Uk banks because they have already lent out all their deposits and much more besides).
Lastly I asked my kids what we had to put into the Golden Coin engine to make it work and produce gold coins: "Chocolate" they replied.
All You Need For Christmas - A Golden Coin motor