t/=8000,

/* main arpeggio (C/F chords) */
p1=t%0.95,
c=Math.floor(t/0.95)%2,
n=p1<0.35?(c?349.23:261.63):
  p1<0.7?(c?440:329.63):
           (c?523.25:392),

/* top layer aligned with chord */
h=c?698.46:523.25,

/* third layer (C6 sequence) */
seq=[1046.50,1174.66,1318.51,1046.50,1396.91,1567.98,1760.00,1567.98], // C6,D6,E6,C6,F6,G6,A6,G6
note_len=0.2375,
idx=Math.floor(t/note_len)%8,
l=seq[idx],

/* final mix */
(Math.sin(6.28318*n*t)*0.5 + Math.sin(6.28318*h*t)*0.3 + Math.sin(6.28318*l*t)*0.5)*0.7*127+128