He drove Gao to his home each Monday morning and drove him back on Friday night. Each work day, he sat next to Gao to learn.

The process of making a velvet flower is monotonous, yet Cai found his passion in this skill. "The feeling of accomplishment when finishing a piece is so good," he says.

"Learning one skill needs patience and time. My master Gao told me if he teaches me one thing a week, there would be something new for him to teach me for more than two decades," he says.

One key step of making the velvet flower is to use copper wire to shape the skeleton. Cai has to crush and rub the copper wire on the fingertips and each time as the wire bites into his hand, it leaves a mark.

"Once your fingerprints are rubbed out, then you are ready to let the copper wire follow your lead," Cai says. The calluses on the thumb and index finger on both his hands are testament to his decades of hard work.

Cai believes that, as time passes, his skill will become more refined and mature, and his works more vivid.

In 2018, when TV drama Story of Yanxi Palace became a hit show, the velvet flowers on the costumes of the actors grabbed the attention of the public.