\subsubsection{$\sqrt{3}$ Refinement}
TODO: an example of $\sqrt{3}$ on a triangle facet: combination 
of the modification operators.


\subsubsection{PTQ and PQQ Refinements}
TODO: an example of PTQ on a tri facet and PQQ on a quad facet:
combination of the modification operators AND modifier + inc. builder.


\subsubsection{DQQ Refinement}
TODO: an example of DQQ on a n-gon facet: modifier + inc. builder.