There's nothing like a few days away to create chaos both before and afterward, as all the normal activities displaced by a trip jostle for attention. So there was a moment this morning when I had to shut myself away with one of my favourite books for restoring my inner tranquillity. It's a small book, Symmetry: The Ordering Principle by David Wade. I bought it randomly a while ago in an art gallery and it's given me great pleasure dipping into it a page at a time.

Each page sets out, step by step. the principles of symmetry in art, nature and the universe, and is accompanied by exquisite line drawings (see the fractals page, below). It's also a delightful little book as a physical artefact, published by Wooden Books. A great stocking filler for the economists and econometricians in your life.