46   r1.setZero();  in triangular_square()
47   r2.setZero();  in triangular_square()
53   m1.setZero();  in triangular_square()
59   m1.setZero();  in triangular_square()
111   m2.setZero();  in triangular_square()
113   m3.setZero();  in triangular_square()
148   r1.setZero();  in triangular_rect()
149   r2.setZero();  in triangular_rect()
155   m1.setZero();  in triangular_rect()
161   m1.setZero();  in triangular_rect()
165   m1.setZero();  in triangular_rect()
170   m1.setZero();  in triangular_rect()
196   m2.setZero();  in triangular_rect()
198   m3.setZero();  in triangular_rect()