cts are written as groups of 4 bits, eg. 1871 = 7 * 256 + 4 * 16 +
15 = [7][4][15]. The high nibble (4 bits) usually determines the effect,
but if it is [14], then the second nibble is used as well.

[0]: Arpeggio
     Where [0][x][y] means "play note, note+x semitones, note+y
     semitones, then return to original note". The fluctuations are
     carried out evenly spaced in one pattern division. They are usually
     used to simulate chords, but this doesn't work too well. They are
     also used to prod