I've now got a reasonably complete set of functions for the pictorial spreadsheet behaviour. Sufficiently complete that it's fun to play with, and see what I can create - or what emerges. This isn't the sense of "emergent" that our arts collaborators typically employ, but is probably related - here we have something that "emerges" from the user's own activity, rather than from the behaviour of the system. Rather close, in fact, to what you might describe as creative experience (or at least playful).
One example of things that have emerged from my own play in the past few days is a photograph that appears from within its own colours, as a sampling window travels over the image, controlling a translucent overlay in the colour of the current sample contents. Hard to show this in a static image, but it's sufficiently pleasant to watch that I left it running for half an hour, and could imagine it hung on a wall as a dynamic picture.
A second (illustrated) example was a dynamic paintbrush, that changes its shape and colour according to position on the screen. This one works under mouse control, so not so suitable as a displayed work (unless controlled by viewers using non-contact sensing), but an effect that can be seen more easily in a screenshot.
Both of these are things that I hadn't expected to create, demonstrate intentions that emerged while I was playing, and had results that were pleasingly surprising. That whole lot come together in a kind of liveness/flow experience. It's possible that Chris already coined a word for this in his PhD thesis, as it's pretty much the same experience that musical composers are looking for. Will have to ask him.