Seeing as how it is the Season Of Trees And Such, I thought that I would post a piece of Code, as an example of Particle Scripting.
This script illustrates two main points:
Particles can last for quite a long time. In this case, the "branches" last for thirty seconds.
The position of particles depends on the prim that is generating them, and one should never be afraid to move this prim as is necessary. You will notice that the "pot" here moves upwards and tilts itself to produce branches at different positions, then moves back to its source when finished. When generating complex particle effects it is often desirable to move the source prim around, or, commonly, to rez other prims which generate particles in different positions and then die.
The script is present in a pot in my Caledon shop, full-permissions and for No Monetary Cost. (It is not, obviously, present on Xstreet.)