I cut some transparent acrylic pencil guides to go along with the 45° Triangle Ruler:

The guides along the rear are the 3D printed versions from a decade ago.
The three transparent guides taught us:
- 4 mm is better than 3 mm
- Entirely transparent guides vanish on the table
So the engraved ring on the two in the front row carries a cheerful Sharpie color to make them stand out. I wanted to use fluorescent acrylic, but I don’t have any 4 mm sheets and stacking a pair of 3 mm sheets → 6 mm will be too thick for the pencil tip.
What looks like dirt on the red guide comes from internal reflections or the lack thereof: it’s perfectly transparent in person, honest.
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