We climb Tryfan on Thursday morning. There is no sun. Yesterday was sunny, tomorrow will be sunny, but today is wet, cold and windy. After 30 minutes of non-stop protesting, they both realise I am not listening, and they do not complain again. Tryfan is mine and Nina’s favourite mountain, it cannot be walked up. You have to scramble and climb. The rocks are wet, both Theo and Isaac get cold hands, but they don’t complain. The way down is even more difficult, jarring and slippery. They just get on with it. I don’t have to teach a single thing. The mountain explains it all.