During the 1970s, and into the 1980s, Abakanowicz changed medium and scale; she began a series of figurative and non-figurative sculptures made out of pieces of coarse sackcloth which she sewed and pieced together and bonded with synthetic resins. These works became more representational than previous sculptures but still retain a degree of abstraction and ambiguity. In 1974-1975 she produced sculptures called "Alterations", which were twelve hollowed-out headless human figures sitting in a row. From 1973–1975 she produced a series of enormous, solid forms reminiscent of human heads without faces called "Heads". From 1976-1980 she produced a piece call "Backs", which was a series of eighty slightly differing sculptures of the human trunk.