This programming language seems like it is mostly targeted at people who need to create graphics in a very structured way. Those that just want to draw or paint may be better served by a digital tablet. However, I think there is a use case for needing a highly rigid, editable description for what you are creating. Perhaps art for boxes or items that could change size could make good use of this type of quickly editable description.
It is easy to adapt elements and to reuse ideas. The concept of rules makes it very easy to take one idea and use it a lot of times. It is also very easy to take an element and change it in a subtle way and see how the change affects the outcome. These are easy because of the encapsulation of shape parts into separate function like elements. These can then be used together to compose the full image.
It is hard to build complicated computations. Multi dimensional loops are possible, but it is hard to do operations much more complicated than addition and subtraction. I created some trees in my program, but when I looked into more complicated fractals it didn't seem feasible. It seems like they have purposely restricted the function set away from more mathematical ideas to preserve simplicity and ease of use.
I looked at sample programs and code in the documentation, the welcome program, and some
forum posts that discussed tricks in the language.
We don't yet have a great definition of the term "computational model". For now, try to come up with the clearest, most concise explanation of what happens when a ContextFree program runs.
A ContextFree program seems very declarative. By this I mean that it seems like programs in context free are executed as
following a tree of rules. The program begins at the root startshape and follows all possible rule paths until there are
no more paths available or the paths get to small to be rendered reasonably (so recursive operations end when the recursion gets down
to the sub-pixel level).
I really liked exploring the gradient abilities in ContextFree. I used a multi-dimensional loop to create a forest that changed hue along one axis and changed brightness along the second axis. I set the size such that the viewer is left with the impression that the forest might extend to infinity.