When he returned to New York, Hassam began a series of "window" paintings that he continued until the 1920s, usually featuring a contemplative female model in a flowered kimono before a light-filled curtained or open window, as in "The Goldfish Window" (1916). The scenes were popular with museums and quickly snapped up. Hassam was especially prolific and energetic in the period from 1910 to 1920, causing one critic to comment, "Think of the appalling number of Hassam pictures there will be in the world by the time the man is seventy years old!" Hassam truly did produce thousands of works in nearly every medium during his life. Where his friend Weir might paint six canvases in a season, Hassam would do forty.