Isn't it amazing...
2007-08-06
...that if you bisect a [regular] tetrahedron just right, the cross-section is square?
I mean, the figure seems at first glance to be all about threes, and yet if you cut it right there's a hidden square inside.
Anyway, while on a mission at the weekend, I found that the suspicious discount superstore near my workplace had these odd little toys reduced to clear. They appear to be called Crazymagz, with or without the 'z'; I'd link but Google only seems to turns up expired eBay wholesale auctions. Which is a shame, because ~£40 all in for a sizeable job lot would have left me with plenty spare to see if london maths teacher or Annie wanted some.
Basically it's a set of small metal rods with a magnet on each end, with metal bearings for the ends. They're wonderful for building geometric figures, especially those that feature equilateral triangles (all the best Platonic solids, for example). It's interesting to see which ones are stable (right-angles don't stay right unless held in place by equilateral triangles, for example): I found that a cuboctohedron shell just collapsed in on itself, until I was messing around building onto a hexagon and accidentally got one with a stable skeleton.
Don't worry if you've no idea what I'm talking about: to appreciate it you've probably got to be a mathematician, a child or a teacher, and even most of those won't share my enthusiasm.
While we're on the subject, did you notice that an icosahedron has vertices described by cycles of {0,±1,±τ}. How did τ get in there!?
I mean, the figure seems at first glance to be all about threes, and yet if you cut it right there's a hidden square inside.
Anyway, while on a mission at the weekend, I found that the suspicious discount superstore near my workplace had these odd little toys reduced to clear. They appear to be called Crazymagz, with or without the 'z'; I'd link but Google only seems to turns up expired eBay wholesale auctions. Which is a shame, because ~£40 all in for a sizeable job lot would have left me with plenty spare to see if london maths teacher or Annie wanted some.
Basically it's a set of small metal rods with a magnet on each end, with metal bearings for the ends. They're wonderful for building geometric figures, especially those that feature equilateral triangles (all the best Platonic solids, for example). It's interesting to see which ones are stable (right-angles don't stay right unless held in place by equilateral triangles, for example): I found that a cuboctohedron shell just collapsed in on itself, until I was messing around building onto a hexagon and accidentally got one with a stable skeleton.
Don't worry if you've no idea what I'm talking about: to appreciate it you've probably got to be a mathematician, a child or a teacher, and even most of those won't share my enthusiasm.
While we're on the subject, did you notice that an icosahedron has vertices described by cycles of {0,±1,±τ}. How did τ get in there!?
Comments