To the uninitiated it resembles synchronised swimming without the water. A dozen people are doing a slow, graceful, silent dance, concentration etched on their faces as they follow instructor Mike Turner.
This is Tai Chi, a martial art developed by Taoist monks in the 13th century. They observed the movements of animals and combined them with meditation to develop these exercises.
The slow movements are designed to create inner calm, and are said to be good for a range of ailments. In the Far East, public parks are full of people engaged in it.
The aim, says one guide, is to develop "the knack of total body awareness and total relaxation," and to "walk like a cat".
There are some warm-up exercises, which include shaking your fingers, then gently bending at the knees. the road to total body awareness looks as though it could be a long and exacting one.
But the tutor begins demonstrating, the class copies him, and gradually hesitant movements become more fluid. The 108 different moves all have descriptive names, such as Stork Cools Wings, or High Pat on Horse. The poetic motions create a gradual feeling of of relaxation.
This evening class attracts a variety of people. Craig Davies, a 27-year-old carpenter, has hair down his back and tattoos up his forearms. "It's a way to sort your head out at the end of a very long day," he says. "I have my own business, and I come here to switch off. When you leave you feel very different."
He admits it is hard to remember the moves. What about practising at home? "I worry about our neighbours' curtains twitching as I attempt Stork Cools Wings on the lawn."
Thankfully, instructor Mike Turner's response to this is typically Taoist. "It's not compulsory," he says. "If you want to that's great. If not,that's fine."
This class took place at Royal Forest of Dean College, Berry Hill,Gloucestershire. Tel: 01594 833416