how much of the rock survives the flat cut — 5.7 splits it in half, 5.10 leaves a nub mm — bows the rock along a fixed X axis into a banana/kidney footprint; 0 = off rerolls seed, spheres, roundness and footprint curve together for a fresh random rock
engraved 0.4mm deep into the flat bottom (mount) face of every hold
sans, serif, monospace, display, script, retro console, and novelty — pick whichever reads best engraved
engrave = recess only; fill = recess plus a matching insert, a second color in the 3MF