A: -------------------------------------------------------- -----------------3 3 3 6---------------------3 3 3------ ---------4 4 4 4----------6 6---------4 4 4 4-------4 6- -4 4 4 4----------------------4 4 4 4------------------- -------------------------------------------------------- -------------------------------------------------------- B: ------------------------------------------------------- -7 6 4-----------------6-----7 6 4--------------------- -------6 4 3-----3 3 3---6 6-------6 4 3-----3 3 3----- -------------6 4-------------------------6 4-------4 6- ------------------------------------------------------- ------------------------------------------------------- C(*): -------------------------6 4 2-----------------------6 4 2- -6 6 6 4 6 7 4 4 2 4 2---------6 6 6 4 6 7 4 4 2 4 2------- -----------------------3-----------------------------------