Daniel began a lifelong habit of recording himself practicing and playing the piano, and then playing the recordings back.
In a 1969 letter to Margy, Mabel wrote, “Danny enjoys playing the piano but I have to push him to practice.” After re-reading the letter to David Thornberry on a 1983 tape letter, he went on to explain, “Mom paid for my sister Sally to have [piano] lessons. Then Sally taught Margy, Margy taught Cindy, and Cindy taught Dick, and Dick and Cindy taught me.”[1]
[1] 7:48, DT005_0 Sept 6 1983 Letter to Dave (San Marcus)