I drink it: a large mouthful. Then I lie down on the sofa and stare at the black circle, concentrating as hard as I can. And this time, I do not fall asleep: I watch as the black circle splits into two, and I try not to blink as it kaleidoscopes around on the sheet, lifting and turning.

And then, in an instant that feels thinner and sharper than the edge of a razor, I’m falling.