The "side-ways rhythm" perception is for the fact of the research that Julia Brown developed about the interpretation of the Baroque Music and Bach in particular. This research is based in the notion that what is written in the score is a basic reference for the execution. Thus, for example, the interpreter can alter the ornamentation, the rhythmic detail, the speed and same to increase some expressivity (characteristics not always clear in the score of those times). I compare with the Pop Music: here the interpreters - singers or instrumentists - have an original text (melody/lyric line, chords progression, regional rhythmic patterns and swing) and they make new arrangements for each show. We should also remind that the Baroque Music was interpreted in the "romantic way" or in a "mechanical way". In the last 20/30 years a movement began (of the which Julia Brown is part) of to go to the Baroque original sources and to rethink the interpretation of these pieces in the encounter of more historical authenticity - or, at least, to try this possibility. The current researchers believe that the Baroque composers had this freedom in mind. It is necessary to remind that Bach, Haendel, Corelli, Vivaldi, Frescobaldi, Couperin, among others, was great masters of the improvisation. There is a good book to begin understand: "Guide to ornamentation in Baroque Music" - H.M. Linde PS: Here in Brazil we used the term "metrica relaxada" ("relaxed metrical" or "loose metrical") for these subtle and expressive alterations of the rhythm. Edson Tadeu Ortolan [log in to unmask]