Most of this video is a handheld-shot look at the inside of this laser cutter that tesla500 seems to have found in the garbage. If you don’t take things apart to see what’s inside, you probably won’t be too interested in most of the content of this video.
Toward the beginning of the video, he shows how the laser beam gets out of the machine. The laser goes through a long “delivery arm” that has many articulated joints and who knows how many mirrors; it’s pretty awesome!
The name “tesla500” might be somewhat familiar with YouTube watchers because he’s the guy who built the “Chronos” camera, which is a low-cost high-speed camera (for recording slo-mo video) and had a Kickstarter campaign for a while. Several of the more popular YouTube creators got early builds of the camera to play with and show off.