From 1959 onward, Williams' work became increasingly abstract and his style was frequently described by art critics as a form of abstract expressionism. While economic factors had originally limited the size of canvas he used, he gradually progressed onto ever-larger canvases, and from 1970 onward also painted a number of large murals. He used glazes and scumbling to create effects with his oil paints. Following a period of self-questioning in the early 1970s, during which Williams worried that he was "only "making" paintings [...] like making wall furniture", he began to re-introduce figurative elements into his paintings—a stylistic change that is particularly visible in his "The Olmec-Maya and Now" series.