Ahead of the first anniversary of Nelson Mandela's death, inmates at a South African prison have been making brightly colored blankets to commemorate the anti-apartheid leader who became South Africa's first black president.

The prisoners at the Zonderwater medium security facility outside Pretoria, the South African capital, have sewn the blankets as part of a charity project for poor communities.

"A lot of them want to make a difference. They want to do something for Nelson Mandela," said Carolyn Steyn, founder of a charity called 67 Blankets for Nelson Mandela Day.

South Africans and others around the world annually mark July 18, Mandela's birthday, with charitable work for 67 minutes to honor what many people refer to as Mandela's 67 years in public service, which include many years as a prisoner of white racist rule.

He died Dec. 5 last year at the age of 95 after a long illness. South Africans were also preparing to pay tribute to Mandela on Friday, a year after his death.

The blanket campaign began earlier this year when Steyn met Mandela's former longtime assistant, Zelda le Grange, and the couple discussed ways to help the disadvantaged.

A Facebook post by Steyn turned into a fulltime campaign that now has a presence in the United States, India, Australia and other nations.

The project extended to the prison yard when Steyn secured a meeting with inmates and a warden. The biggest obstacle was ensuring that crochet hooks would not be used as weapons and the prison has since devised a system to keep track of crocheting prisoners.

Steyn taught prisoners in orange jumpsuits how to make a simple chain of stitches. Fast learners were soon teaching other inmates.

Steyn says prison wardens have noticed that the crocheting prisoners have become more placid. She hopes that one day they'll make blankets for their families, and perhaps even their victims.