Look at the way he has it setup for the Y - It's not a full cutout, it's just a half/3quarter engraving with pin holes.
Then watch the video again from 1 - as the camera pans around, you see the rest of the letters are hollow... and somehow get filmed in black. I thought it was because he had everything cutout and just had a black sheet/4x8 under it... but now it looks more like video editing / photoshop.
If you look at the metal bar under the yetis beard... It goes from straight to distorted immedietly.
View attachment 143713
then 1:14 - 1:20 you see the camera panning... theres nothing behind the I and L.. then as soon as he gets over it, it looks like he placed a letter in.
Ignoring the distorted media holder.... Maybe he did something weird with the camera angle, but I don't see why Y would be a percision cut with pin holes, then L and I would be a complete cutout that somehow turns into a black letter as he pans over it.
Maybe I'm missing something, or seeing it differently... It just seems fishy to me! Cutting something like this should be easy on any CNC, I dont get why the Y would be pinhole mounted, and the rest is a pure cutout though.