CoCalc -- char.max.2

GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it

⁵⁶¹⁰⁶⁸ views

10x5	% 
 1  1 2 2  2
 1  2 2 2  4
 2 -2 0 0  0
 2  2 2 2 -2
 2 -2 0 0  0
 0  2 1 1  2
 2  0 1 1  2
 0  2 1 1  2
 2  0 1 1  2
 2 -2 0 0  0