Six coasters with concentric ring engraving. Speed 100mm/s, 30% power for the rings, 60% for the rim cut.
What I learned
Bamboo grain runs both ways in 4mm sheets. Engrave parallel to the dominant grain so the rings stay crisp.
Failures, kept on purpose.
The mistakes that taught me the constraints. Every workshop post keeps these, they're more useful than the final photo.