Harold Zisla (1925-2016) trained as a representational artist, following its tenets from his youth until his mid-50s, when he broke through to abstraction. In more than 100 sketchbooks, he produced scores of oil crayon sketches, as many as 20 in a day, ranging from images that float on the page to those that are anchored by robust colors and forms; he also captured portraits and nude figure drawings. In works on paper, he created hundreds of images ranging from Zen-like simplicity to complex webs of line and color using oil crayon, china marker, watercolor, Magic Markers . . . whatever was at hand. And, in painting, he shifted from oils to acrylics, valuing its immediacy; continued to experiment with ways to frame panels for maximum impact; deepened his use of gesture; and explored the potential of color, from the bold to the nearly monochromatic. This gallery presents a sampling of key styles.