Tom & Jerry cartoon split an island in half with a big wall, creating two islands.
Tom was on the sun lounger, enjoying his holiday on his side of the island. If he wanted something, he just pressed the buzzer.
Jerry, the waiter, served him from the other side of the island.
Tom pressed the buzzer repeatedly.
Tom got a massive kick out of pressing the buzzer.
And Jerry kept serving him.
Each time, Jerry's side of the island had a little less growing on it.
Eventually, there was nothing left.
On one side of the wall, the island was still a land of plenty.
But on Jerry's side, the island was barren.
It was a moment when something big clicked for me.
As a 7-year-old, it was right up there with the day I found out no one lives forever - the day Tarzan died.
And the day Father Christmas wasn't real - the day I spotted the next-door neighbour putting the costume on in the garage.
This Tom & Jerry cartoon had taught me more about economics and sustainability than any book would.
The planet has limited resources.