

Fresnel lenses (like the kind you can tear out of old projection tv’s) work great for that, but they’re kind of a pain and bulky, and very impractical. I have one I took out of an old 55" projection tv. I think charcoal firestarters by a tire works better and can be “deployed” in seconds, but concentrated light is still pretty cool. This vid shows how well they can work.
My music folder is 8006 files (53.7GB) but I probably only listen to maybe 200 of them that are actually in my normal playlist.