IndexedLineSet

Definition :
IndexedLineSet { 
  eventIn       MFInt32 set_colorIndex
  eventIn       MFInt32 set_coordIndex
  exposedField  SFNode  color             NULL
  exposedField  SFNode  coord             NULL
  field         MFInt32 colorIndex        []
  field         SFBool  colorPerVertex    TRUE
  field         MFInt32 coordIndex        []
}
Explanation :

The IndexedLineSet node represents a 3D geometry formed by constructing polylines from 3D points specified in the coord field. IndexedLineSet is specified in the local coordinate system and is affected by parent transformations.

color : If this value is not null, then this either effects the vertices or faces defined by this IndexedFaceSet node.
coord : defines the vertices of the polygon.
colorIndex : defines a color for each vertices.
colorPerVertex : defines what kind of color is going to be used for each polygon and vertices. This controls all the possible coloring strategies.
coordIndex : defines each poylgon by using point indexes.