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9 dots laid out on a background in a 3 x 3 grid the background is blue, the dots are a brighter shade of blue, except for one -- the one you're focused on if you focus on the center dot, it looks PURPLE while the rest look blue if you shift your focus to the lower right dot, THAT dot looks purple, and the center dot (along with all the others) looks blue and so on

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9 dots laid out on a background in a 3 x 3 grid the background is blue, the dots are a brighter shade of blue, except for one -- the one you're focused on if you focus on the center dot, it looks PURPLE while the rest look blue if you shift your focus to the lower right dot, THAT dot looks purple, and the center dot (along with all the others) looks blue and so on
https://media.mas.to/media_attachments/files/116/156/026/567/394/477/original/1ee07599e9ffb60d.jpg

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Kim Scheinberg (kims@mas.to)'s status on Monday, 02-Mar-2026 06:31:10 JST Kim Scheinberg

This is a very cool optical effect
Whichever dot you focus on looks purple while the others look blue
As someone whose eyes have been "settling" from cataract surgery followed by a superficial keratectomy in one eye, and has noticed my vision changing daily at various focal points, this is fascinating
https://arxiv.org/pdf/2509.11582v2

In conversation about a month ago from mas.to permalink