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Snow in the Desert

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source: https://dia-algerie.com/neige-recouvre-dunes-de-sables-a-ain-sefra/

source: NASA Earth Observatory

via [NASA Earth Observatory]

[Image] Archimedes’ screw

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[Image] Archimedes' screw

In the Netherlands, some of the windmills used to drain the polders at Kinderdijk have been replaced by modern Archimedes screws.

Image by: M.A. Wijngaarden
License: CC Attribution-Share Alike 2.5 Generic license.