matrix := [
[6,0,0,0,0,0,0],
[0,0,5,0,0,0,0],
[0,0,0,0,5,0,0],
[0,0,0,0,0,5,0],
[1,5,5,4,0,2,0],
[4,4,2,5,0,3,0],
[5,4,0,0,1,5,1]
]*Z(7);