his previous films, adding: "We finally wound up talking with someone who had a close connection to Stanley Kubrick's lawyer. We suddenly got an invitation to fly to London." Before Carlos knew about the offer, she read the book and began writing a piece based on it named "Timesteps". A soundtrack containing only the film cuts of the score was released as Stanley Kubrick's Clockwork Orange in 1972, combining synthesized and classical music by Henry Purcell, Beethoven and Gioacchino Rossini with an early use of a vocoder. The album peaked on the Billboard 200 chart at No. 146. Later that year, Carlos released an album of music not included in the final score titled Walter Carlos' Clockwork Orange. Carlos later described the project as "a lot of fun ... a pleasurable venture". Carlos experimented with ambient music on her third studio album Sonic Seasonings, released as a double album in 1972, with one side-long track dedicated to each of the four seasons. Recorded as early as 1970 and finished in mid-1971, before the A Clockwork Orange project was complete, Carlos wished to produce music that did not require "lengthy concentrated listening", but more than a collection of ambient noises to portray an environment. It combined field recordings of animals and nature with synthesized sounds, occasionally employing melodies, to create soundscapes. It reached No. 168 in the Billboard 200 and influenced other artists who went on to pursue the ambient and new-age genres in later years. By 1973, Columbia/CBS Records had received a considerable number of requests for Carlos to produce another album of synthesized classical music. She agreed to the request, opting to produce a sequel to Switched-On Bach, which began with her and Elkind seeking compositions that were most suitable for the synthesizer; the two picked selections from Suite No. 2 in B minor, Two-Part Inventions in A minor and major, Suite from Notebook for Anna Magdalena Bach, and Brandenburg Concerto No. 5 in D major. The latter features a Yamaha E-5 Electone organ for certain passages, as a reliable polyphonic keyboard had not been developed. The result, Switched-On Bach II, was released in 1973 and sold over 70,000 copies in the US during the first five weeks of its release. Following Switched-On Bach II, Carlos changed musical directions once more. In 1971, she and Elkind had asked Columbia Records to attach a pre-paid business reply card in each