Agnes Martin built her oeuvre around the search for sublime beauty and serenity, following her belief that “art is the concrete representation of our most subtle feelings.” Her fine-lined grids, bands, and square blocks of pale, lightly applied color fused the emotional resonance of Abstract Expressionism with the spare purity of Minimalism. Martin’s mastery of line and grid was a great source of inspiration to artists like Eva Hesse and Ellen Gallagher, and her work is often discussed alongside Sol LeWitt’s famed wall drawings. The square is integral to Martin’s work, both as the shape of her canvases and as an enduring motif, influenced by the Taoist pursuit of balance and harmony. “My paintings are not about what is seen,” she said. “They are about what is known forever in the mind.”