Looking for laser pointer example

I'd like to find an example of a particle script that does a laser pointer. I've been playing for a while and read the llParticleSystem() wiki, but can't get a long line that looks like a laser pointer. All I can make is a short red line - 1 m or so long.

I need something many meters long - 50m or more. And so I can direct it. I'll figure the rotations if I know where to put them in. I"m gonna look at PSYS_SRC_TARGET_KEY, but I'd rather have a beam based on source prim rotation to start with.

Thanks much,

wwv