As well as quilts and beanies, John has just finished a backpack for his 15-year-old sister. At times he gets frustrated, "but when it's finished I feel proud, like I've achieved something."
Sewing instructor Joanne Hammerton said the programme was set up two years ago for industrial sewing in what used to be a gym in the Kea youth unit. The course had become more creative since she began in April, the inmates typically making prisoner rain ponchos and bookbags for a children's charity in the morning, then quilts in the afternoon.
"When I first brought some quilts in they just laughed. But some of the stauncher ones gave it a try and the rest followed," she said.
Sewing helped pass the time, gave the inmates a creative outlet and helped them relax, she added. One had told her he now understood why old ladies did it, because it had stopped him stressing about his release date.
Prisoners were interviewed and had to show good behaviour to get onto the course, which was limited to eight at a time. They also had to win prison officers' trust, because scissors and needles were involved.
Some were incredibly skilful, Mrs Hammerton said. One had used a needle for the first time four months ago and now outdid her in embroidery.
"He's a natural. To go from not knowing anything to working at this standard in a short time is exceptional," she said.
Prisoners were often waiting outside the workshop in the morning, and had to be ordered out in the afternoon.
"When I arrive at 8am and the boys are already knocking on the door, that proves they're keen," she added.