A Gallery of Interactive On-Line Geometry
At the Geometry Center.
Archimedes' Book of Lemmas
A collection of all 15 propositions from Archimedes' Book of Lemmas with complete proofs, each accompanied by a Java illustration.
Bette Veteto's Homepage
History of Mathematics, very strong on geometry.
A collection of interactive geometry applets. Topics include polyhedra, Poncelet's porism, Soddy's hexlet, Mandelbrot set, Steiner porism, Pappus's chain, Repulsion polyhedra and stereo pictures.
Conjectures Produced by the Program Graffiti
Graffiti is a computer program that makes conjectures in mathematics and chemistry. Links to the conjectures and bibliography.
Cut the Knot
Features articles about specific problems, illusions, and puzzles. Includes diagrams.
Encyclopedia of Triangle Centers
By Clark Kimberling. Over 1000 triangle centres in a searchable compilation with diagrams.
Erich's Packing Center
Graphics and links for various packing, tiling and covering problems.
Fundamentals of Geometry
Free online book on geometry in pdf format. Contains material not easily found elsewhere from detailed exposition of elementary absolute geometry based on Hilbert's axioms to more advanced topics.
A new type of geometric construction that was discovered by Dan Litchfield and David Goldenheim. Includes general explanation and sketch examples.
Geometric Group Theory
Information and resources about geometric group theory and low-dimensional topology. People, groups, meetings, links.
Web site for the (now closed) Center for the Computation and Visualization of Geometric Structures at the University of Minnesota. Graphics, multimedia, software, teaching resources.
Geometry Formulas and Facts
Excerpts from the 30th Edition of the CRC Standard Mathematical Tables and Formulas (1995), namely, the geometry section minus differential geometry.
Geometry and the Imagination in Minneapolis
Geometry exercises for a two-week summer workshop led by John Conway, Peter Doyle, Jane Gilman and Bill Thurston at the Geometry Center in Minneapolis, June 1991.
Geometry from the Land of the Incas
Presents problems involving circles and triangles, with proofs, SAT practice quizzes and famous quotes. Also, has examples of geometry in Peruvian culture.
Geometry in Action
Includes collections from various areas in which ideas from discrete and computational geometry meet real world applications.
Geometry/Topology at Michigan State University
Activities of the geometry/topology group at Michigan State University.
Offers a variety of resources for teaching and learning about geometry. Problems and theorems are presented with step-by-step solutions for each proof.
Math Forum: Geometry.research
Discussion board for geometry professors and instructors to keep informed of the latest research.
Math Forum: Search geometry-forum
Those interested in examining the previous incarnation of the Math Forum may search the archives of the Geometry Forum.
Mathematical Curves and Surfaces
Graphical representations of computer generated forms. (French/English).
NPR : Mathematicians Get Crafty with Geometry
A husband and wife from Cornell University have come up with a crafty way to illustrate high-level geometry concepts -- by manipulating yarn into models that help explain the curvature of spaces. The mathematicians talk with NPR's Jacki Lyden about hyperbolic crocheting. [4:47 streaming audio broadcast]
Includes packings of equal objects in containers together with source codes to obtain them numerically.
Shows paper models of polyhedra.
Problem of the Minimum Rotation Surface
Java applet demonstrating the catenary.
Sangaku: Reflections on the Phenomenon
Critical reflections on the sangaku phenomenon accompanied by a collection of solved sangaku problems, many with interactive Java illustrations.
The Complete Quadrilateral
Several properties of the complete quadrilateral illustrated with Java applets
The Entropy Reduction Laboratory by Karl-Dietrich Neubert
Discusses double shell structured periodic systems, platonic spheres, molecular and crystal structures, and FlashSort algorithms.
The Geometry Junkyard
Usenet clippings, web pointers, lecture notes, research excerpts, papers, abstracts, programs, problems, and other stuff related to discrete and computational geometry.
The Lepidoptera of the Circles
The Butterfly theorem and its generalizations illustrated by Java applets.
Wilson Stothers' Inversive Geometry and CabriJava Pages
Includes Steiner's Porism and the arbelos.
Xah's Personal Page
Features an illustrated dictionary of special plane curves, a paper on wallpaper groups, mathematics image gallery and links to software packages.