Over the weekend, after months of pressure from my children, I started playing Minecraft on my iPhone. The children play it on the iPad, in creative mode, trundling around in unlimited diamond armour. Being an adult, I settled into survival mode: spawned onto the savanna, got slaughtered by monsters of the night for a while and eventually dug a secure, well-lighted home into the side of a little mountain. The children coached me on how to make a bed and build a furnace and grow wheat.