🚀 go-pugleaf

"Waterfall display" sounds like what I have seen [*] called a "cascade
plot".  Usually they were a representation of how the frequency
content of a signal changes over time - ie. they were FFT spectra
taken over successive intervals, in a pseudo-3D representation.

Draw FFT#1 at the baseline.
Draw FFT#2 at the baseline + dX,dY; choose dX,dY so that you get very
    nearly parallel lines, and not too much detail is hidden behind
    the peaks (actually, varying dX,dY interactively can be very useful
    too. Sort of like looking at a signal in perspective - but different).
Ditto FFT#3, 4, 5...

This gives you a 3D looking plot where you can see the frequency components
changing over time. Patterns emerge very clearly.


In my own work I have used cascade plots to inspect computer performance 
data, like variations in kernel profiles according to workload.  Occasionally
I have wanted '4D' or greater type cascade plots, where the underlying
data is more than 2D, varying over time.



[*] Hell, I'll be honest: "I have seen" == my Dad uses; my Dad is one of the
    Vibrations Analysis wizards that kept the Canadian Navy going on the
    oldest destroyers in the world.  I keep thinking that some knowledge
    engineer should interview him to build an expert system for this sort
    of maintenance and signal processing, now that he's retired.
--
Andy "Krazy" Glew,  Motorola MCD,    	    	    aglew@urbana.mcd.mot.com
1101 E. University, Urbana, IL 61801, USA.          {uunet!,}uiucuxc!udc!aglew
   
My opinions are my own; I indicate my company only so that the reader
may account for any possible bias I may have towards our products.