Complex sentence: After experimenting with glassblowing, Ries began working in the classical reductive technique, beginning with large blocks of optical glass and reducing them to the desired form by carving, grinding, and polishing them.
Split into simpler sentences: After experimenting with glassblowing, Ries began working in the classical reductive technique. He begins with large blocks of optical glass and reduces them to the desired form by carving, grinding, and polishing them.