Math Forum Internet News

Volume 3, Number 52

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28 December 1998                                   Vol. 3, No. 52


Patterns/Symmetry - Britton | Projective Geometry | USDA-NASS Kids Page

                       - Jill Britton

Annotated links to 30 activities at a variety of Web
sites, coordinated with Exploring Pattern: Symmetry and 
Tessellations, a book by Jill Britton to be published 
in March 1999 by Cuisenaire/Dale Seymour. 

Britton has assembled links to resources that illustrate
symmetry in wheel covers, paper dolls, butterflies,
traffic signs, beehives, quilts, the alphabet, hex signs,
cast iron decorative work, snowflakes, the Alhambra, and 
more. Topics include:

  -  introduction to symmetry
  -  symmetry in the alphabet, flags, and quilt blocks
  -  reflectional and rotational symmetry
  -  strip patterns
  -  regular and irregular polygons
  -  paper-folding and cutting
  -  origami
  -  tessellation in nature
  -  kaleidoscopes
  -  regular, semiregular, and demiregular tessellations
  -  Islamic tessellations
  -  M. C. Escher
  -  jigsaw puzzles
  -  tessellating art
  -  explorations with TesselMania


               PROJECTIVE GEOMETRY - Nick Thomas                


Projective geometry regards parallel lines as meeting in an 
ideal point at infinity, and is concerned with incidences: 
where elements such as lines, planes, and points either
coincide or not. For example, Desargues' Theorem says that
if corresponding sides of two triangles meet in three points 
lying on a straight line, then corresponding vertices lie 
on three concurrent lines. The converse is also true: if 
corresponding vertices lie on concurrent lines, then 
corresponding sides meet in collinear points.

This handsome site provides some basics; information about 
and illustrations of path curves, counter space, and pivot 
transforms; short biographies of some people involved 
in the development of projective geometry; and references.


                     USDA-NASS KIDS PAGE 
           National Agricultural Statistics Service,
                U.S. Department of Agriculture

Stanley Stat and Pie-Chart Pam introduce elementary and 
middle school students to statistics, and demonstrate how 
important they are to agriculture. The site is organized 

 - history of agricultural statistics and NASS 
 - games, including jokes and a coloring book
 - What does NASS do in your state?
 - Words We Use, a short glossary
 - cool links on agriculture

Kids may e-mail questions about agricultural statistics
to the site:


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