Category Archives: eBay

Polyhedral Modeling, Using Steel Balls and Cylindrical Magnets

Many commercial products are available to model polyhedra, such as Zometools, Stella 4d, Polydrons, Astro-Logix, and magnetic spheres which can be assembled into polyhedral shapes, sometimes with brightly-colored struts for the edges of the polyhedron. The first three tools, I … Continue reading

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An Ethical Dilemma Involving a Polyhedral Crystal

I just ordered a crystal rhombcuboctahedron on eBay because I like its geometrical properties, despite the mystical claims in the item listing. I did so with the full knowledge and expectation that these claims are almost certainly false, because, well, … Continue reading

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How to Distinguish Real from Fake Silver Bullion

It seems a certain teacher, with 19 years’ experience teaching chemistry, has written a guide, for buyers on eBay, to help them avoid getting ripped off by the (tiny) minority of eBay sellers who sell fake silver. If you buy … Continue reading

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