Making synthetic holograms with a CNC mill

Doc writes in –

Making lo-rez holograms on a CNC – Figured you guys might get a kick out of this, as the fellow not only made his own CNC mill (including using homebrew laser interferometry to determine how flat the table is, and anodizing it himself) but has recently been experimenting with CNC engraving.

Making synthetic holograms with a CNC mill – Link.