Going from a simple chart looking like this:
which doesn't give a clue as to the frequency of each event, to something like these two:
I had to go from a simple list of three items (a,b,c) to go to an (n by n) block in excel which could then be plotted as a bunch of 3d shapes/
Well, at least I know what to do, so it will be easier for the next couple of charts :-)