Just to clarify what I am looking for a bit: what is usually known as
"visual programming" [creating code by directly linking and annotating
graphical representations of language constructs] is only of secondary
interest to me right now -- useful to me primarily for how they
represented the language constructs in a visual fashion. My primary
interest is in capturing and presenting dynamic code (and data) behavior
in a clean, efficient manner. As a zero-th approximation of what I am
initially shooting for, take a look at "Bridging the Gulf Between Code
and Behavior in Programming" by Henry Lieberman and Christopher Fry,
which describes the ZStep 94 debugger (for Macintosh Common Lisp) - see: 

http://lieber.www.media.mit.edu/people/lieber/Lieberary/ZStep/ZStep.html

>From the help you all have given, I have been able to find a number of
sites about SV (I feel rather like Johnny Five, "Input! More input!") --
so I should be able to stay off the streets and out of trouble for a
while :-). Thanks! 

-- Dwight

Dwight Hughes wrote:
> 
> I am looking for good papers and/or books on software visualization --
> especially as pertains to reversible debuggers (logically reversible -
> not thermodynamically reversible :-b), code animation, and data
> animation (and algorithm animation in general). I have started with some
> of Henry Lieberman's papers and would like to know what else might be
> out there, or if others here have experience with this. (Yes, this _is_
> about Squeak -- I want to create a new debugger for Squeak based on
> these techniques.)
> 
> I would love to get some Smalltalk references, but Lisp, Prolog, or
> whatever are just fine.
> 
> Thanks.
> 
> -- Dwight