After a repeat, the riff is followed by a variation. Motive y, which includes the final three chords, is removed and replaced by a half-note rest, and the overall pattern is truncated from four measures to two.
The removal of the latter three chords and related subtraction of two measures from the pattern has the effect of accelerating the riff. By shortening the musical idea and compressing the space in which it works, the variation brings about an intensification of the activity and directs a focus on the tritone relationship between the power chords on Gb and C at the end of the pattern.