Remember MRS GREN, the mnemonic for the biological features necessary for organic life? Movement, Respiration, Sensation, Growth, Reproduction, Excretion, Nutrition. The great shared factor – the one that is present in them all – is movement, which occurs at some level, micro or macro, during every one of these functions. This intimate association between life and movement is reflected in human languages, which are laden with movement-related metaphors, imagery and symbolism. In English, for example, we speak of life cycles and seasonal cycles, of money or kindness making the world go round, of giving the nod or of shaking things off. We advise ‘going forward’ and ‘moving on’. We run ideas past other people; we are caught on the hop; we leap to conclusions; we take it step by step. Life, we say, is a journey. Sometimes we see the path clearly and lope along. Sometimes, however, we can’t see the woods for the trees, or our plans are stalled, or the wheels fall off, and everything comes to a grinding halt.