Nowhere-neat tilings are actually pretty neat. We all know you can't "square the circle", but do you know the story of squaring the square? (And by the way, even if you can't construct π with a ruler and compass, you can come awfully close without too much work.)
posted by Wolfdog on Dec 4, 2007 - 10 comments

How did the Polynesians navigate without maps? And where did they get to? [Previously]
posted by djgh on Aug 31, 2007 - 28 comments

The most dangerous toys of all time. Lawn darts? Check. Cabbage Patch Dolls that chewed off your fingers? Check. Working radioactive U-238 Atomic Energy Lab? Check. To spark more memories of holidays past, peruse the 10 weirdest toy ads of all time, and don't forget the Cheap Toy Roundup if you don't have enough cash. Or you could always get a Talking Jesus from Toys for Tots.
posted by blahblahblah on Dec 13, 2006 - 62 comments

Jim Loy's Mathematics Page is (among other things) a collection of interesting theorems (like Napoleon's Triangle theorem), thoughtful discussions of both simple and complex math, and geometric constructions (my personal favorite); the latter of which contains surprisingly-complex discussions on the trisection of angles, or the drawing of regular pentagons.

Similarly enthralling are the pages on Billiards (and the physics of), Astronomy (and the savants of), and Physics (and the Phlogiston Theory of), all of which are rife with illustrations and diagrams. See the homepage for much more.

If you like your geometric constructions big, try Zef Damen's Crop Circle Reconstructions.
posted by odinsdream on Sep 14, 2005 - 8 comments

Galileo's compass (with sound). Galileo Galilei's compass resembles a calculator. In Le Operazioni del Compasso Geometrico e Militare (Padua, 1606), Galileo describes over 40 operations that can be carried out with this instrument. Try using the compass yourself.
posted by matteo on Feb 25, 2005 - 6 comments

Find out where you stand with the political compass.
posted by Mocata on Jun 6, 2001 - 26 comments