Another Music Puzzle

The characters will arrive at the edge of a huge pit.  They must get to the far side to retrieve another instrument for their quest.  Eight stone discs, big enough to stand on, float magically in open space over the pit.  Each disc has a number associated with it from one to eight as indicated by diamond-shaped markings.  The markings are configured like the symbols on playing cards, while the discs are arranged in a pattern relative to each other as shown in the diagram to the right.

The characters will be able to hear a simple, repeating melody playing overhead.  The melody will correspond to the root notes of a standard jazz progression:

I  vi  ii  V  I   (1, 6, 2, 5, 1, or  C, A, D, G, C)

This is the order that the characters will have to tread the discs in order to get to the other side.  Stepping on any of the discs out of order will dump the character into the pit below.  The minimum weight to activate a disc is 50 lbs, so the players won't be able to easily test them. The distances between the discs will be such that the PCs can jump from side to side (e.g., from  #3 to #2), or from one row to the next (e.g., from #2 to #4), or even diagonally to the next row (e.g., from #2 to #7), but they won't be able to skip rows (e.g., from #2 to #8).

You may have noticed that they will not be able to make it back to disc 1 from disc 5.  The players will need to make the connection that #8 can serve as a substitute to #1, just as the 8th note of a major scale is the same note as the 1st note in the scale, just an octave higher.  So the true pattern is 1, 6, 2, 5, 8.

This will not be an easy puzzle for them.  The pit won't be save or die, of course, but I will put something creepy down in the bottom - and a way to get back up on the near side - to add to the excitement.