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List of planar symmetry groups

 
Wikipedia: List of planar symmetry groups

This article summarizes the classes of discrete planar symmetry groups:

  1. 1 simple symmetries (reflection)
  2. 2 infinite set of point groups
  3. 7 Frieze groups
  4. 17 wallpaper groups

Contents

Simple symmetry

Point groups:

Example Symbols
GeometricKite.svg
Example:Kite
(*)
Reflection symmetry

Point groups

There are two classes of point groups, rotational and reflectional.

Point groups:

Example Symbols
Flag of Hong Kong.svg
Example:Flag of Hong Kong C5
Cn (n)
Cyclic group
Snowflake8.png
Example: Snowflake D6
Dn (*n)
Dihedral group

Frieze groups

There are also 7 Frieze groups in the plane which have a fundamental line of symmetry and infinite fundamental domains.

Example
pattern
orbifold notation
patterns for the 7 frieze groups
  1. (∞∞)
  2. (∞x)
  3. (∞*)
  4. (*∞∞)
  5. (22∞)
  6. (2*∞)
  7. (*22∞)

Wallpaper groups

There are 17 wallpaper groups in the plane with finite fundamental domains.

Rotation
Wallpaper group diagram p2.png p2 (2222)
parallelogrammetic
Wallpaper group diagram p4.png p4 (442)
Wallpaper group diagram p3.png p3 (333)
Wallpaper group diagram p6.png p6 (632)
Maximum symmetry per lattice type
Wallpaper group diagram pmm.png pmm (*2222)
rectangular
Wallpaper group diagram cmm.png cmm (2*22)
rhombic
Wallpaper group diagram p4m.png p4m (*442)
square
Wallpaper group diagram p6mm.png p6m (*632)
hexagonal
Mixed
Wallpaper group diagram p3m1.png p3m1 (*333)
Wallpaper group diagram p31m.png p31m (3*3)
Wallpaper group diagram p4g.png p4g (4*2)
Other
Wallpaper group diagram pm.png pm (**)
Wallpaper group diagram p1.png p1 (o)
Wallpaper group diagram pg.png pg (xx)
Wallpaper group diagram pmg.png pmg (22*)
Wallpaper group diagram cm.png cm (*x)
Wallpaper group diagram pgg.png pgg (22x)

Note: with regard to the number of mirrors p4m is "more symmetry" than p4g, with regard to the size of the fundamental domain it is an "equal amount of symmetry".

See also

External references


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Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "List of planar symmetry groups" Read more