Easy beam shaping/focus?

Anyone seen a post or internet link to a discussion on how to focus and shape a beam?

I'd like to come up with an easy mod for the UK 4AA AS2 lamp module or the PT Rage lamp module that will focus the light into the tightest spot possible (something like the Stealthlite spot). Ideally, this would be something I could fabricate and just place around the bulb on top of an existing module.

...but, I don't know anything about the shape of a reflector to achieve a tight spot. Any ideas or resources for me?

Thanks!

I don't know much about lenses, but the relfector can only produce a spot as tight as it is designed for. Move it out of focus, and you will increase the beam size.

Good question. I'm also wondering about the principles involved here.

Alternately, any chance that one can just use a tiny magnifying glass to focus the items tighter.

MO