If you live in the SF Bay area, BESTs now has the Impossi-ball, as
well as most of the other better group-theory puzzles at fairly
reasonable prices. Rubik's Revenge is $9.00. The Impossi-ball
was in the Scientific American column; its the icosahedron-like ball
with 2 each of 6 colors (as Alexanders Star). If fact, I think it
is equivalent to the star. It doesn't look as good, but the mechanism
is more clever; what's more, you can remove one face and use it as a
sliding block puzzle. Has anybody seen the other new puzzles from the
column?
-- Stan
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