Complex sentence: He developed techniques of coloring the outside of plastic blocks and of laminating plastics of different color, but by 1980 Byng had stopped making sculpture and was moving back to painting, partly due to the toxicity of plastics.
Split into simpler sentences: He developed techniques of coloring the outside of plastic blocks and of laminating plastics of different color. By 1980, Byng had stopped making sculpture and was moving back to painting, partly due to the toxicity of plastics.