Complex sentence: John Rutherford Armstrong (14 November 1893 − 19 May 1973) was a British artist and muralist who also designed for film and theatre productions, but is most notable for the Surrealist paintings he produced.
Split into simpler sentences: John Rutherford Armstrong (14 November 1893--19 May 1973) was a British artist and muralist who also designed for film and theatre productions. He is most notable for the Surrealist paintings he produced.