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Drag the arrows to see how two mirror flips equal one rotation in 2D and 3D
Rotation via Double Reflection
Hacker News ·
by Laszlo Korte
An interactive page that builds up a rotation by reflecting a vector twice, with colored formulas that match the drawn arrows. You can drag points and watch the angle and result update.
Notes
Assumes some comfort with vectors; maker doesn't state how it was built.
Source checked 2026-10-16. Descriptions summarize the maker's own account, not independent testing.
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