PYRAMID Gallery, in Stonegate, York, is celebrating 21 years under the stewardship of owner Terry Brett with an exhibition by Beryl Cook and York Artists that opens on Saturday at 11am.

On the walls will be screen prints by Cook; on the plinths will be ceramics by Peter Humpherson, recycled glass by Suzanne Dekker, glass sculpture by Andy Griffiths and sculpture by Jonathan Newdick and Stan Sandig.

To mark the occasion, Pyramid has commissioned Suzanne Dekker to make 21 “Lucky Tokens”. “These are small leaf shapes that will be hung on trees around the city of York on Saturday,” says Terry. “Finders of these tokens may keep them as pendants or bring them into the gallery in exchange for a gift voucher to the value of twice the edition number on the token.”

In other words, a token marked as 10/21 may be swapped for a gift voucher to the value of £20 for spending in the gallery; token number 21 for a voucher worth £42.

“I wanted to mark my 21st year at Pyramid Gallery, and when I discovered that Suzanne had produced ‘Lucky Tokens’ in glass for people to find at Glastonbury Festival, I realised that this would be a perfect way to celebrate the occasion,” says Terry. “Suzanne has now specially made 21 that are numbered and have our website, pyramidgallery.com, in lettering inside the glass.”

Beryl Cook’s limited-edition screen prints in this exhibition are a selection from 27 original prints she produced with publishers CCA Galleries and are all signed by the late artist in pencil.

Beryl’s life story took her from being a showgirl and working in the fashion industry in London, to running a pub with retired Merchant Navy husband John and moving to southern Rhodesia in the 1950s.

One day there, she picked up her son’s paints and started a picture. She carried on doing so, using various materials, painting on scraps of wood, fire screens and a breadboard.

In 1963, the Cooks returned to England to live in Cornwall, where she began to paint seriously. Moving to Plymouth, they ran a busy theatrical boarding house in the summer months and enjoyed watching flamboyant drag acts. Beryl concentrated on painting in the winter months, recreating her personal views of Plymouth in oils on wooden panels, whereupon an antique dealer friend persuaded her to let him try to sell a few. They sold quickly.

Once Bernard Samuels, of the Plymouth Art Centre, became aware of this “local phenomenon”, he convinced her to have an exhibition. The 1975 show resulted in a cover feature in The Sunday Times magazine, followed by her first London show in 1976 at the Portal Gallery, where she exhibited until her death in 2008.

Suzanne Decker studied at York College from 2004 to 2010, first leaded glass, then kiln-formed glass, before graduating with a first class degree in contemporary 3D crafts.

“My work is constantly inspired by nature,” she says. “I have a strong interest in the work of British Land Artists. Most of my work is made from window glass that would normally end up in landfill; re-using glass is something that I’m passionate about and I’ve been working with it for the past few years.”

• The 21st anniversary exhibition will run at Pyramid Gallery from Saturday to July 14.