German pianist Wilhelm Backhaus types on a Remington portable typewriter while playing the piano at the same time. From Typewriter Topics, 1922.
Look, ma! No hands (on the typewriter, that is!):
Backhaus in 1920
Backhaus (March 26, 1884-July 5, 1969) was one of the first modern artists of the keyboard. He was particularly well known for his interpretations of Beethoven and romantic music such as that by Brahms. He was also much admired as a chamber musician. He was an enthusiastic user of Bechstein pianos and Remington portable typewriters.
Born in Leipzig, Backhaus began learning piano at the age of four. He toured widely throughout and made his US debut on January 5, 1912, as soloist in Beethoven's 5th Piano Concerto with Walter Damrosch and the New York Symphony Orchestra. In 1930 he moved to Lugano and became a citizen of Switzerland. He died, aged 85, in Villach in Austria, where he was to play in a concert.
Composer Robert Stone does it differently.