Seurat labored extensively over A Sunday on La Grande Jatte—1884, reworking the original as well as completing numerous preliminary drawings and oil sketches (the Art Institute has one such sketch and two drawings). With what resembles scientific precision, the artist tackled the issues of color, light, and form. Inspired by research in optical and color theory, he juxtaposed tiny dabs of colors that, through optical blending, form a single and, he believed, more brilliantly luminous hue. The very immobility of the figures and the shadows they cast makes them forever silent and enigmatic. Like all great masterpieces, La Grande Jatte continues to fascinate and elude.