Have been listening to this song for the past few days. The melody is
quite simple and with a catchy rhythm, it stays in your head. But,
the brilliance of this song lies in the extraordinary harmonic
accompaniments, especially the vocal sections. Vocal layerings are
out of this world. During the rap section, the female vocal harmonic
accompaniment is just beautiful with an Indian classical melody and
soft vocal tones. And finally, the chord progressions in the song are
ABSOLUTELY BRILLIANT. It's the chordal progressions which add those
special "surprise" elements throughout the song, as if on a journey
with breathtaking twists and turns. Rahman using a lot of minor 6th
and 7th triadic variations which add an immense richness to the
harmony. Especially take note the ending, when Rahman starts
singins "Round and round....". The chords in that section are
mindblowing. I tried playing that on my keyboard and they are tough
to follow, but I eventually figured them out with a lot of effort and
time.