\fill

Description 

\fill is used to fill the area with a one of the two defined colors. First parameter is a flag symbol to determine which color has to be used. Following others parameters are symbol name of vertices defining the area to be fill. Vertices have to be given in a circular order but the closure of area is automatically done by joining first and last vertices. Once an area is filled in a step, this filled area is added to the end of the area list stored to be filled. In other words, the filling order of areas is chronological, first defined first drawn.
This operator should only appear within a step block.

Usage

  \fill(front, a, b, c, d); % fill initial square
  \fill(back, a, b, d);     % if c comes to a 

Formal structure

  \fill(SIDE, VERTICES_LIST);

Parameters

  SIDE
  Description    : Indicates which color has to be used.
  Type           : Side type.
  Allowed values : One value of [back, front].

  VERTICES_LIST  : Vertices defining area to fill.
  Type           : List of vertex symbols.
  Allowed values : Any sequence of vertex identifiers already 
                   defined in previous steps.