system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: When a logo, image or anything is etched on a surface via a laser, why is it always there a final pass that runs throughout the image?
gpt
If you try to draw with a ballpoint pen~~cil~~, when you fill up an area you will first scribble in one direction which fills 95% of it, then scribble in an other direction to fill the remaining 5%.

Laser engraving try to fill up surfaces with a line. The problem is a surface is 2d while a line is 1d-ish. There is some thickness to it but in between the lines there might be some remaining paint to etch. So you finish the job by having a faster finishing pass in a different orientation to clean up anything remaining.