22 lines (21 with data), 271 Bytes

in2.ine
begin
16 6 integer
1 -1 0 -1 0 0 
1 -1 0 0 0 -1 
1 0 -1 -1 0 0 
1 0 -1 0 -1 0 
1 0 0 0 -1 -1 
0 -1 1 0 0 1 
0 1 -1 0 1 0 
0 0 0 -1 1 1 
0 0 1 1 -1 0 
0 1 0 1 0 -1 
2 -1 -1 -1 -1 -1 
0 1 0 0 0 0 
0 0 1 0 0 0 
0 0 0 1 0 0 
0 0 0 0 1 0 
0 0 0 0 0 1 
end
nonnegative