The more I use periaktoi, the more possibilities I see in them. I’ve been using them now for about six years for staging all sorts of school productions, and they’re an astoundingly simple and effective way of setting a scene.

Periaktoi are tall, thin, triangular prisms, like up-ended Toblerone packets, about seven feet tall. We make them from huge sheets of cardboard (six feet by seven feet), folded into three and stuck together with sticky tape.We use about six - three at each side of the performance area - but you can use more or fewer depending on how much space you have.

On the three facets you create three different visual effects, then during the production you rotate the periaktoi to change the scenes. Because they’re so light, any child can move them. I tape marks on the stage to show the correct position.

As the name suggests, they’re an ancient theatrical device, used by the Greeks and the Romans. According to my Brewer’s Dictionary of the Theatre, they were first described by one Marcus Vitrius Pollio, who lived from 70-15bc. The name - periaktos in the singular, periaktoi plural - means “revolving”, and I presume the Greek versions were made of stone. They were rediscovered during the Renaissance and improved - using removable canvas panels - but they must have gone out of fashion again when proscenium arches came in.

Our former head of art, Frank Draper, introduced them at Chafyn Grove about 10 years ago. Usually we paint scenery on them, with help from the art department. You place three periaktoi corner to corner against each other like a wall and paint a scene right across. Then you can either position them close together at the sides of the stage, or space them out so they act like wings, giving different exits and entrances.

Recently I used them in a very modern play, painted in plain colours; we just switched from orange to bright yellow halfway through, and it was very effective. We’re fortunate in that we also have super lighting at the school, but even without lighting you can get some great effects - changing from a bright daylight scene to a night sky, for instance.

Between productions you can paint them in a neutral colour such as grey, and use them to hide yukky corners of the hall! Because we do a lot of productions, we also tend to replace a couple each year - we get the cardboard direct from the manufacturer, measure it, score it with a Stanley knife so it bends in the right place, make the periaktoi and have a mega-painting party. Recently we made 12 for Pounds 40.

Despite their being light and easy to move, I’ve never had any problem with them falling over, but if you were doing something like a dance production and wanted to stabilise them you could put a sandbag inside. They are such a wonderfully simple and useful device; everyone who sees them says, “Why didn’t we think of that!” Jane Dickson is head of drama at Chafyn Grove School, a prep and pre-prep school in Salisbury