X en la calle 13 reflects Sarah Grilo’s experiences of living in New York City during the 1960s. This period marks an important transition in her work as she moved away from her earlier geometric paintings focused on color harmonies. Here, she mixed the techniques of Informalism with the use of language to suggest the graffiti and splashes of color one finds on a gritty urban wall. Her operation is somewhat paradoxical since it is the walls themselves that acquire the look of abstract paintings over time.