STRUCTURE – the division of the whole into parts.  The structure of Cage's early Nocturne is intuitive and improvisatory, guided by the composer's moment-to-moment CHOICES.  Soon afterwards Cage was to begin using a technique of rhythmic structure which allowed him to place MATERIAL selected from a GAMUT of sounds into a pre-formulated framework in which the proportions of the small parts which together make up each large part are reflected in the proportions of the large parts which make up the whole.  The Eight Whiskus each consist of several short phrases which pivot around a single pitch expressing the MESOSTICkey of the original vocal version. In the late NUMBER pieces, the structural parts are varied and flexible in length due to the use of TIME BRACKETS.