A while back I posted about these things called L-Systems, which are a way of programmatically generating images based on some fairly simple rules.
As it turns out, you can do some pretty nifty things. The initial images that I put up in my last post used a turtle-graphics type of rendering based on the output of the L-System after a certain number of iterations. I'm doing the same thing here, except it is now a 3D turtle with a number of other things it can do like change colour, change the width of the line, draw polygons, etc.
Here's a few examples. A tree (this one is generated completely deterministically, which is kinda cool):
Here's a nice little flower bush. This one uses stochastic rules for colouring the flowers:
These programs are all in 3D, so if you download the actual code you can circle around the plant, zoom in, etc. Unfortunately I was a bit lazy with the camera system so it is a bit annoying sometimes, but it works well enough.
You can check it out yourself here at the Github repo. I'll be putting up a little guide in the Wiki shortly, so check back there if you want to know how the "language" for the system works.