P :=
12 9
   1    1    0    1    0   -2    0    0    0
   1    1    0   -1    0    0    0    0   -1
   1    1    0    0   -2    0    0    0    0
   1   -1    2    0    0    0    0    0   -1
   1   -1    0   -1    0    2    0    0    1
   1   -1    0    0    2    0    0    0    1
   1   -1    0    0    1    1    0    0    0
   1    1    0    0    0    0   -2    0    0
   1   -1    0    0    0    0    2    0    1
   1    1    0    1    0    0    0   -2    0
   1   -1    0   -1    0    0    0    2    1
   0    2    0    0    0    0   -2   -2   -2
;
assert((card P) = { });
