Has anyone done CNC inlays before?

I was exploring some cnc project ideas and came across this inlay video. I am wondering if it’s more complicated then it seems here?

I know @RealCarlRaymond was trying some of these!

In fact i followed this video. I got pretty good results, although i discovered how much slop there is in the X axis.

One of my many planned projects is to make an idler pulley to take the slack out of the belt, and then do some more of this.

I’m happy to help if anyone wants to try this.

I am definitely interested, i am a little confused on why they rest the z on the extruding side. I will try to pick your brains at some point