The moiré effect lights that guide ships home
Why Hacker News recommends it
Linked as the accessible explanation of how moire navigation lights work.
What it is
Tom Scott investigates moire-effect beacons, called Inogon leading marks, a Swedish invention from the 1980s that shows different patterns depending on the viewer's position. He visits one used to mark an undersea cable and tracks down its history.
Recommended by 1 HN commenters across 1 different months, 2024 to 2026.
What Hacker News said
Recommends wgrover · 2024-02 · on “Light characteristic”
You might also find moiré-effect navigation beacons interesting, like the one that Tom Scott visits here: [this video]
Cites dublinben · 2024-09 · on “Using the moiré effect to show different arrows to each observer (2018)”
This is nothing but blogspam of the embedded Tom Scott video: [this video] . This article adds nothing that is not already included in the video itself.
Cites notpushkin · 2026-08 · on “Guiding Ships with Moire Patterns”
It is used and I guess it works largely the same way as in author’s first picture: you get arrows pointing towards where you should correct your course to. Tom Scott has made a video on those: [this video]