"E.T.I." is written for four percussionist to play a variety of different instruments, including chimes, field drum, thunder sheet, brake drum, various cymbals, toms, bass drum, marimba, and snare drum.  The pitched instruments are not used for melodic purposes at all, and pitches changes merely divide phrases, rather than create counterpoint.  The interest of the piece come from the rhythm, 4 against 3 specifically.  It is used as a tempo modulating tool and to create tension between the instruments.  There are times when the instruments seem to move freely from one another only to sync back up rhythmically a few measures later.