In 2007, Niels Meulman — an artist and graphic designer based in Amsterdam — invented the neologism "calligraffiti" to describe his work, which fuses calligraphy and graffiti. But that's only part of Meulman's vision. His new work incorporates Abstract Expressionism, and so a canvas like Unfollow looks like it was done by the progeny of Jay DeFeo and Johannes Gutenberg. Blotches and splashes of paint hang out with stylish gold-and-green lettering to create a cosmos of form and feeling. Unfollow is one of some 20 new Meulman works on display in "Unism," a White Walls exhibit that will be a stirring revelation to anyone unfamiliar with the artist's career. Meulman, 45, has exhibited at White Walls before, and his work is included in the permanent collection of SFMOMA. With a background in graffiti, advertising, and formal design, Meulman incorporates a wide swath of influences to create works that feature repeated patterns of letter swoops, and words that begin with "un," as in "unaware" and "unjustified." "Traditional handwriting with a metropolitan attitude." That's how Meulman has described his work. The attitude, and the language he plays with, reaches a creative peak with "Unism."