triangular mesh
 

Hi all
i created a very simple 2D model: two blocks connected with a thinner block. Using the mesh created by blockmesh i get reasonable results, while using a mesh with triangular cells with same cell lengths, no internal angle less then 45 deg. i am getting results surely not valid.
First question: the usage of triangular cells does make sense?
Second question: does the orientation of faces (i.e. sequence of numbering of points definif a face) can explain the difference of results?
Third question: checkMesh tool could be a useful tool to understand the validity of the mesh, where can i find the definition of check actually done by checkMesh?
thank you
neri alamanni