The pool of water that appears on a hot road is not wa and n a refle of t sky i any ordi sense. T layer res on t hot tar is hotter and rarer than the air above it, and a ray travelling downwards through those layers is bent until it turns upward again into the eye. What arrives is a patch of sky delivered from below, which is why the false pool holds the colour of the sky and retreats as you approach it.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.