### ----------------------------------------------------
### -- Math::Quaternion
### -- Licenses: Artistic-2.0
### -- Authors: 
### -- File: logotype/logo_source.txt
### ----------------------------------------------------
# Method to create logo:
    cd logotype
    curl -O http://www.fileformat.info/info/unicode/char/210d/doublestruck_capital_h.svg
    /Applications/Inkscape.app/Contents/Resources/bin/inkscape --export-area-drawing --export-width=32 --export-height=32 --export-png=logo_32x32.png doublestruck_capital_h.svg



# Source of logo
From http://en.wikipedia.org/wiki/Quaternion :
    The algebra of quaternions is often denoted by H (for Hamilton),
    or in blackboard bold by  (Unicode U+210D, ℍ).

From http://www.fileformat.info/info/unicode/char/210d/ :
    Name	DOUBLE-STRUCK CAPITAL H

Examples of U+210D in various fonts:
    http://www.fileformat.info/info/unicode/char/210d/fontsupport.htm

Of the fonts, these would be acceptable:
    Arial Unicode MS
    Code2000
    Code2001
    DejaVu Serif
    DejaVu Serif Condensed
    Symbola
As seen here:
    http://www.fileformat.info/info/unicode/font/arial_unicode_ms/u210D.png
    http://www.fileformat.info/info/unicode/font/code2000/u210D.png
    http://www.fileformat.info/info/unicode/font/code2001/u210D.png
    http://www.fileformat.info/info/unicode/font/dejavu_serif/u210D.png
    http://www.fileformat.info/info/unicode/font/dejavu_serif_condensed/u210D.png
    http://www.fileformat.info/info/unicode/font/symbola/u210D.png

However, only one (Arial) has the character in svg:
    http://www.fileformat.info/info/unicode/char/210d/doublestruck_capital_h.svg



# Other candidates for logo/icon:
http://en.wikipedia.org/wiki/File:Quaternion2.png
    Graphical representation of quaternion units product as 90deg-rotation in 4D-space.
    Raster only; would have to convert to vector by hand.
http://en.wikipedia.org/wiki/File:Quaternion_Plague_on_Broom_Bridge.jpg
    Original definition.
    Raster only; ill-sized.
i2 = j2 = k2 = ijk = − 1.
    Fundamental definition. (the 2s will be superscripted)
    Does not fit well into a square logo.
http://en.wikipedia.org/wiki/File:Cayley_graph_Q8.png
    Cayley graph of Q8.
    Raster only; would have to convert to vector by hand.
http://en.wikipedia.org/wiki/File:Slerp_factor_explanation.png
    Oblique vector rectifies to Slerp factor.
    from http://en.wikipedia.org/wiki/Slerp
    Raster only; could convert to vector by hand, but perhaps large enough to resize OK?
    Slerp not relevant enough to Quaternion to use as logo, I think.


