The version I posted in Projects & Ideas had two layers that read as one. Redrew layers 2 and 3 so each aperture is about 65% of the one in front, and stained layer 4 with a light walnut. Completely different piece.
Build
Five layers of 3mm birch ply, cut in one session on the LP4. Spacer rings of the same 3mm ply between layers, glued at six points around the circumference so the glue never shows through an aperture. Backing plate has a routed channel for a 12V warm-white strip — 3000K, anything cooler makes birch look grey.
What I'd do differently
Mask the front face before cutting. I cleaned smoke residue off the outermost layer for twenty minutes and you can still see it in raking light if you know where to look.
The apertures on layer 1 are slightly too fine for the material — a couple of the thinnest bridges scorched through on the inside curve. 1.8mm minimum on 3mm birch, not 1.4mm.
