I’m on a bench outside a hut halfway up a mountain in Austria. There’s a fresh beer in front of me the size of a small vase, foam still holding its shape. Ten meters down the path, Jorrit and Tijmen are dragging rocks into a shallow stream to build a dam. They’re three. The dam is not going well. Dad might have to help (he loves building dams). But not yet. The sun is warm and there’s a book on my…