Fractal:

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   Generates fractals. Pass a vertex list, face list, depth of the fractal
   generation and the standard deviation of the height increment. This 
   routine requires that the face list contain only triangles. The algorithm
   adds new vertices at each midpoint displaced in the direction of the 
   triangle normal a random amount determined by sigma. Each pass generates
   7 triangles for each existing triangle.

   Type Fractal for a demo.
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   -------
   Inputs
   -------
   v           (:,3) Vertex list
   f           (:,3) Face list
   n           (1,1) Fractal depth
   sigma       (1,1) Standard deviation of height change

   -------
   Outputs
   -------
   v           (:,3) Vertex list
   f           (:,3) Face list

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Children:

Common: Graphics/NewFig
Common: Graphics/XLabelS
Common: Graphics/YLabelS
Common: Graphics/ZLabelS