Polyedergarten - Shows paper models of polyhedra. 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. GLaD Comments - A new type of geometric construction that was discovered by Dan Litchfield and David Goldenheim. Includes general explanation and sketch examples. Erich's Packing Center - Graphics and links for various packing, tiling and covering problems. Geometry in Action - Includes collections from various areas in which ideas from discrete and computational geometry meet real world applications. The Geometry Junkyard - Usenet clippings, web pointers, lecture notes, research excerpts, papers, abstracts, programs, problems, and other stuff related to discrete and computational geometry. Bob's Pages - 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. Packomania - Includes packings of equal objects in containers together with source codes to obtain them numerically. 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. The Entropy Reduction Laboratory by Karl-Dietrich Neubert - Discusses double shell structured periodic systems, platonic spheres, molecular and crystal structures, and FlashSort algorithms. Conjectures Produced by the Program Graffiti - Graffiti is a computer program that makes conjectures in mathematics and chemistry. Links to the conjectures and bibliography. Geometric Group Theory - Information and resources about geometric group theory and low-dimensional topology. People, groups, meetings, links. Geometry Center - 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. A Gallery of Interactive On-Line Geometry - At the Geometry Center. 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. 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] The Complete Quadrilateral - Several properties of the complete quadrilateral illustrated with Java applets The Lepidoptera of the Circles - The Butterfly theorem and its generalizations illustrated by Java applets. Archimedes' Book of Lemmas - A collection of all 15 propositions from Archimedes' Book of Lemmas with complete proofs, each accompanied by a Java illustration. 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. Cut the Knot - Features articles about specific problems, illusions, and puzzles. Includes diagrams. Sangaku: Reflections on the Phenomenon - Critical reflections on the sangaku phenomenon accompanied by a collection of solved sangaku problems, many with interactive Java illustrations. Geometry/Topology at Michigan State University - Activities of the geometry/topology group at Michigan State University. Go Geometry - Offers a variety of resources for teaching and learning about geometry. Problems and theorems are presented with step-by-step solutions for each proof. Problem of the Minimum Rotation Surface - Java applet demonstrating the catenary. Bette Veteto's Homepage - History of Mathematics, very strong on geometry. Wilson Stothers' Inversive Geometry and CabriJava Pages - Includes Steiner's Porism and the arbelos. Mathematical Curves and Surfaces - Graphical representations of computer generated forms. (French/English). Encyclopedia of Triangle Centers - By Clark Kimberling. Over 1000 triangle centres in a searchable compilation with diagrams.