Think of collecting cards as cryptocurrency
You and your friends have a collection of cards for your favourite sport. You haven’t got all the cards to complete the collection yet.
You keep all your cards in a locked box along with your friends’ locked boxes in the same locked room. You have the key to your box and need to keep it very safe — if you lose it, your box could be taken by someone else or lost forever. You can see which cards everyone has on the outside of the box.
Any of you can go look at your own cards and see which cards your friends have. You can send and receive cards to or from any of your friends. Each time any card is moved, the list on the outside of the box is updated.
Sometimes, you want a card in one of your friend’s boxes that a few others want as well. This makes certain cards quite popular and valuable. It requires you to swap some other cards over for that card. The friend that is able to swap the best cards for that valuable card will get the card. That same card might also stop being so popular and you wont need to swap as many cards for it anymore.
New friends might also set up boxes in the same room. They can come in and buy cards from the boxes that are already there. As there are only a certain number of cards in the entire collection — the more people with boxes in the room will make the cards worth more.
The cards can even be used to buy things like toys outside the room where certain shops take cards for payment of toys. The shop will have a box in the room. The more cards you have in your box, the more toys you can buy.
On top of all this there a number of toy trains working hard and fast to deliver the cards to all the boxes when you or your friends move them about. To reward the train driver for doing this work, the ones that are fastest get new cards for the collection into their own box.
The important thing to remember is that the cards are owned by everyone with boxes in the locked room and everyone can see who has which cards and where cards have been swapped.