Geometry and the Discrete Fourier Transform

Revised version of a November 2011 Feature Column on the AMS website. The underlying technologies changed and so tweaks had to be made in order that it function as intended, and, indeed, how it used to. I kept an older version if you want to see it.

Web Geometry: some simple uses of the Geometer's Sketchpad Java Applet

Note these demonstrations use the Geometer Sketchpad Java applet, so they will not display in Google's Chrome browser after Version 42, or in any other browser which does not have a modern Java plugin activated.

• An ancient triangle
• A (regular) triangle of centroid 0
• A regular triangle and anti-triangle
• A regular pentagon and anti-pentagon
• A regular pentagram and anti-pentagram
• A regular pentagon and pentagram
• A regular pentagon and an anti-pentagram
• Square and Anti-Square Averaged
• Square and Anti-Square and Dipole Averaged

Related links to some even linkages. These were Flash animations on 12 Sep 2016. and used to be Java applets. Now they seem to point to a scam or porn site. So they are disabled by putting two spaces in the schema of the old URL: on http: //www.mekanizmalar.com.]

• "http: //www.mechanisms101.com/tchebicheff.shtml": Chebyshev's Straight-line Mechanism at http: //www.mechanisms101.com
• "http://www.mechanisms101.com/watts.shtml": Watt's Linkage at http: //www.mechanisms101.com

         [Last Modified: Friday, 7-Nov-2025 18:02 EST]