This is the most bizarre sanding solution I’ve ever seen. Called the Sandsall, it consists of two separate handheld power tools, and the sanding element is connected between them:
This gives you a better look at the system, and different elements you can swap in:
Outside of the louver-sanding part of the demonstration, I’m not convinced of the tool’s utility, though I do like to see experimental thinking.
That being said, I assume this never made it to market. The video is dated 2018, but here in 2021 the homepage on the company’s Spartan website says “Testing is Underway.”