Very cool (note that you can place the light and drag it's direction)!

One thing I noticed is that this visualizes how dangerous laser light can be. A lot of DIY projects these days use lasers (SLA printers, Laser cutters). You can't warn people enough about the risks when working with lasers.

This app shows how laser light bounces around in ways you don't expect.

Edit: and ofcourse the rest of his portfolio is great: https://benedikt-bitterli.me/portfolio.html