Geomag bar lengths and ratios
Posted: Thu Nov 05, 2009 4:00 pm
The classic Geomag bars are approximately 27mm long and the new ones are 58mm,
the balls remain 12.7mm diameter.
Rounding slightly: that's 1" for old bars, 2-1/4" for new bars, and 1/2" balls.
For polyhedron building, what matters is the "distance between centers" which is,
therefore, 1-1/2" for classic and 2-3/4" for kids.
The ratio between these two is 11:6 (1.83) which isn't close to any
useful ratio I can think of.
Two ratios that would have obvious uses are: the cube diagonal (1.73) and the
golden ratio (1.61).
I happen to have a few 3/4" balls and see that for this size of ball the ratio is 1.71.
Here's a pentagram with 3/4" balls:
See that the edges aren't quite straight. Also, at the sharp points the balls don't quite seat correctly because the rods interfere with each other.
the balls remain 12.7mm diameter.
Rounding slightly: that's 1" for old bars, 2-1/4" for new bars, and 1/2" balls.
For polyhedron building, what matters is the "distance between centers" which is,
therefore, 1-1/2" for classic and 2-3/4" for kids.
The ratio between these two is 11:6 (1.83) which isn't close to any
useful ratio I can think of.
Two ratios that would have obvious uses are: the cube diagonal (1.73) and the
golden ratio (1.61).
I happen to have a few 3/4" balls and see that for this size of ball the ratio is 1.71.
Here's a pentagram with 3/4" balls:
See that the edges aren't quite straight. Also, at the sharp points the balls don't quite seat correctly because the rods interfere with each other.