Writing and drawing are major forms of graffiti. Artists write letters and words with spray paint, while drawing is aimed at creating patterns. There is also commercial graffiti, with artists being paid by companies to create work for them.

Some brands who want to connect with the younger generation invite graffiti artists to work on designs for them. Zheng's team decided to form a company at the end of 2016 to take commissions from brands.

All four members of the team are married and have children. "We need to take responsibility for our families, and our graffiti skills help us to design works that showcase our strengths in painting about traditional Chinese culture," said Zheng, who is the company's CEO.

The four have been creating graffiti since they graduated from college.

They take a two-month break from design work every year, devoting themselves to creating graffiti on the streets instead. Last year, they staged the Golden Flow graffiti contest in Ningbo for new street artists, which attracted a dozen groups from China and about 30 from other parts of Asia.

Using the profits they made from running the company, they declined sponsorship for the contest, enabling the event to represent "pure street art".

Zheng said, "When organizing the competition, we encountered many surprises, but they were all good ones, such as the help we received from a hotel and a mall that provided the venue."