Tristano's band had two recording sessions in 1949 that proved to be significant. The sextet recorded original compositions, including his "Wow" and "Crosscurrent", that were based on familiar harmonies; reviewers commented on the linearity of the playing and its departure from bebop. Without a drummer, the other musicians also recorded the first free improvisations by a group – "Intuition" and "Digression". For these tracks, the sequence in which the musicians would join in the ensemble playing, and the approximate timing of those entrances, were planned, but nothing else – harmony, key, time signature, tempo, melody or rhythm – was prepared or set. Instead, the five musicians were held together by contrapuntal interaction. Both tracks were praised by critics, although their release was delayed – "Intuition" was released late in 1950, and "Digression" not until 1954. Parker and composer Aaron Copland were also impressed. Numerous other musicians of the time, however, thought Tristano's music too progressive and emotionally cold, and predicted that it would not be popular with the public.