[citation needed] During the very early 1980s he started producing work on canvas, shown by galleries and bought by museums and private collectors.

[citation needed] He continued to paint New York City subway trains until 1989, long after increased pressure from the MTA had stopped many from doing so.

[citation needed] His more recent work includes three-dimensional sculpture, mixed media work with reclaimed or discarded materials (often found in the street), and a series of hand-painted MTA New York subway maps.

He continues to exhibit worldwide and produce work with and alongside artists such as Banksy.

[1] He has his own clothing line that prints t-shirts with his lettering and comic hero renderings.