Ellsworth Kelly's work in the 1960s continued his exploration and expansion into abstract art, with a particular focus on the relationships between shape, color, and form. This period marked a significant evolution in Kelly's artistic journey, as he began working with irregularly angled canvases and introduced his first shaped canvas, "Yellow Piece" (1966). This work signified a pivotal moment in Kelly's career, as it demonstrated his break from traditional rectangular supports and redefined the figure/ground relationship in painting. The use of a single, all-encompassing color in this piece emphasized the canvas as the composition itself, transforming the wall behind it into part of the artwork (Wikipedia). During this time, Kelly's experimentation with form and color became more pronounced, with a notable shift towards larger formats and monochromatic panels. His work provided a bridge from American geometric abstraction of the early 20th century to the minimalism and reductive art that characterized the mid-1960s and 1970s. Kelly's interest in the natural world, as seen in his early fascination with bird watching, continued to inform his abstract compositions, where simplicity and direct observation played crucial roles. The influence of nature and Kelly's observations from birdwatching can be seen in his use of vibrant colors and straightforward forms, mirroring the clarity and precision found in the natural world (www.wikiart.org). Kelly's contributions during the 1960s were instrumental in the development of hard-edge painting, a style characterized by sharp, precise edges and clear color delineation. Despite being associated with Minimalism, Kelly's unique approach preceded the movement by a decade, establishing him as a leading figure in the hard-edge style. His work from this era reflects a deep engagement with the visual phenomena of the world, distilled into abstracted forms that resonate with viewers for their purity and perceptual clarity (Encyclopedia Britannica). The 1960s were a transformative period for Kelly, as his art continued to challenge and redefine abstraction. His legacy from this decade endures, highlighting his innovative contributions to modern art and his influence on subsequent generations of artists (Wikipedia) (The Art Story) (Encyclopedia Britannica).