When I was a bit older, I could go out by myself into the small garden which we had. My favourite game was playing with water. Children’s toys were not available, except some made in wood by my father. Food was severely rationed, and could only be obtained by government-issued coupons. The country was dependent for much of its food upon the cross-Atlantic convoys, which, though escorted, often suffered losses as a result of constant attacks by German U-Boats.
People were encouraged to do what they could to grow food of their own in their gardens. My father joined a small consortium which raised a pig, augmenting our very limited supplies of food. Garden-railings were removed to be melted down for munitions.
But in our small garden, my mother would take out a container with water in it. And a few small cups or other vessels. I amused myself by transferring the water from one vessel to another, and so on. Possibly I learned something from this. (Click for a brief note on Piaget).