One of the first things I learned to do when I was a teenager, and my parents finally put a chunky computer on my bedroom desk, was to figure out which set of three keys to press to make the programs I was using suddenly close. That way, when I heard my mom's footsteps approaching my door, with a flick of my wrist I could quickly make that blog I had when I wasn't allowed to blog, or that messaging app I used to chat when I wasn't allowed to chat, disappear.

You can try it lying in bed, in front of a mirror, or even from inside a bathtub full of water. To achieve this, he explains Gabriel Ventura in the essay The best of impossible worlds (Anagram, 2025), "it requires a bit of concentration and following a few steps." The most popular method is the one known as the crow. To try it you have to be "very tired or in a state of deep relaxation." Believe, slightly bent - emulating the wings of a crow - and legs apart, you close your eyes, and while counting to one hundred, as many times as necessary, you repeat to yourself: "I can move to any universe I want." If you start to hear a tingling in your hands and feet it is a good sign: the head is showing its head.