The 'transformation crystal ball'
If we read the row of notes as we read the Zodiac from Aries on downwards, the following little scale appears, which was later called a 12-tone lake.
Per Nørgård called this motif the 'transformation crystal ball' because of the row's ability to transform its appearance depending on where one laid the stress when playing it:
..when I played it [the transformation crystal ball] [..] [I] was able to
make the little scale fluctuate in five quite different tonal aggregates (pentaton -A and
-E flat, an augmented triad, or as the case may be, a whole-tone third on G, A, and Bb.)
(see the postscript on page 64 in Jørgen Mortensen: Per Nørgårds Tonesøer (Per
Nørgård's Tone Lakes)).
Apart from this tonal fluctuation, the transformation
crystal ball is itself a beautifully formed motif.
And it was a motif which Per Nørgård felt called to extend and expand.
