In the middle section ("poco più animato"), characterized by rhythmic shifts and sudden harmonic turns, theme and accompaniment are fused into oscillating double notes. There are five eight-bar phrases. Leichtentritt observes that each eight-bar phrase is "ruled by a new motif" and that "each of these segments surpasses the preceding one in sonority and brilliancy". The third period, although it stays chromatically centered around E major, is a long sequence of diminished seventh and tritone intervals, littered with accidentals and irregular rhythms difficult to play. It reaches a climax in the fourth period (bars 46–53), a bravura passage of double sixths for both hands. The fifth period (bars 54–61), leading back to the final restatement of the theme, can be described as an extended dominant seventh. Leichtentritt believes it to be "one of the most exquisite sound impressions ever contrived for the piano". Its effect is "based on its contrast with the fourth period and on the gradation of the most tender nuances in piano". The final A section is a quite literal though shortened restatement of the first one. At the end of the étude the fair copy autograph contains the directive "attacca il presto con fuoco" which means that Chopin foresaw the joint performance of both this étude and the following one.