Perpetual Motion Machine

Performance Guidelines -
Perpetual Motion Machine is an open score with an infinite number of possible versions. The guidelines below are just suggestions for possible realisations. The performer is invited to follow as many of them as seems appropriate. The guitarist is also at liberty to construct a version of the piece by inventing their own guidelines.
Beginning and ending
Perpetual Motion Machine is a piece without a specified beginning or ending. The player can start and finish anywhere they like. The piece could simply begin, or fade in. To finish, the piece could simply stop, it could fade out at full speed or it could slow down to a halt and not fade out.
Structure -
There are three and a half minutes of musical material, but the piece could last as little as a few seconds, or go on for several hours.
The performer does not have to play all the material in the score.
The letters in boxes in the score give the performer the opportunity to jump around.
x and y are linked to alternating semi-tone patterns that can act as portals. The player can jump from any x to any other x, and from any y to any other y. Note that x always starts on the pitch C and y always starts on E.
The bass notes that start various measures and are marked E, F, A, D, f, are portals to any other measure marked in the same way.
For example, instead of playing measure 17 (marked f), you could jump straight to measure 18, 30, 89, 90, 116, 140, or 142 instead (also marked f).
Any fragment of music (a passage, a measure, a part of a measure) can be repeated one or more times before moving on.
In places, the guitarist could get stuck in a groove and repeat a short section many times. In others, the player could simply play through the material presented in the score.
The piece should be different every time it is played. The structure could be planned in advance, or improvised in performance.
It is also possible to play the piece all the way through as written, with or without repeating it.