Pieces known by Delia
Electronic Study 2 (1954)
In it, "he selects quite a constricted range of material, the proceeds to cover it totally, to use up all the possibilities that the imagination considers worth while".
Studie 2 is eighty-one sine tones pitched along an exponential frequency scale which spans just over seven octaves. The steps are all perceived as equal and are a little over 1/16th of an octave in size. [...] The most significant thing about these intervals chosen by the 25th root of 5 is that no octaves occur. The lowest frequency is 100 c.p.s, and no multiple of 100 by any whole number occurs throughout the scale.
Gesang der Jünglinge (1955-56)
Jonathan Harvey says that "the overall structure of Gesang der Jünglinge is remarkably like that of Electronic Study 2; both final sections combine and develop the ideas stated in the preceding sections."