text: In the standard Coltrane change cycle the ii–V–I is substituted with a progression of chords that cycle back to the V–I at the end. In a  piece, each chord gets two beats per change.
  Coltrane developed this modified chord progression for "Countdown", which is much more complex. At its core, "Countdown" is a variation of "Tune Up", but the harmonic substitutions occur rapidly and trick the listener into thinking that they are listening to a completely unrelated tune.  The ii, V and I remain, but in between are other chords (highlighted in yellow and blue) from the major thirds cycle centered around each I. Preceding the first chord of each major thirds cycle is its V chord.
  An earlier Coltrane piece, "Lazy Bird", also features two tonal centers a major third apart in its A section.
  Giant Steps
  The "Giant Steps" cycle is the culmination of Coltrane's theories applied to a completely new chord progression. Coltrane uses the cycle in descending major third tonal transpositions in the opening bars and then ascending ii–V–I progressions separated by a major third in the second section of "Giant Steps". The second section is basically the inverse of the bridge section described in "Have You Met Miss Jones" above.