1 P3

     2 # example from the man page

     3 4 4

     4 15

     5  0  0  0    0  0  0    0  0  0   15  0 15

     6  0  0  0    0 15  7    0  0  0    0  0  0

     7  0  0  0    0  0  0    0 15  7    0  0  0

     8 15  0 15    0  0  0    0  0  0    0  0  0