Seen here, NATRL, a wildstyle graffiti artist, has tagged this wall in San Francisco with all the intricacy of a Celtic illuminated manuscript. 

Wildstyle graffiti emerged from New York in the 1970s and 80s and is characterized by its highly elaborate letterforms and patterns that nearly lose all legibility.  The San Francisco wildstyle is particularly intense and intricate with finer and more frequent strokes than its eastern counterparts.  The compact intricacy of this localized style further disguises the type to the point that it is nearly indistinguishable without prior knowledge of the artist's tag. In this particular tag, the strokes overlap and interweave with one another so complexly that it begins to resemble and extensive Irish knot pattern. Its vibrant colors and highly textured pattern draws viewers in, and then the intricacy forces them them to sit with it for a bit to be able to understand what it actually says.

NATRL wall tag in San Francisco Bay Area.
NATRL wall tag in San Francisco Bay Area.