Mosaic matrix

This isn't a matrix, especially if it is supposed to be graphical; it's a very small (or extremely low resolution) bitmap.

sub checker ($n) { (^$n).map: { 1 xx $n Z× (flat ($_ %% 2, $_ % 2) xx *) } }

.put for checker 7;
put '';
.put for checker 8;

Output:

1 0 1 0 1 0 1
0 1 0 1 0 1 0
1 0 1 0 1 0 1
0 1 0 1 0 1 0
1 0 1 0 1 0 1
0 1 0 1 0 1 0
1 0 1 0 1 0 1

1 0 1 0 1 0 1 0
0 1 0 1 0 1 0 1
1 0 1 0 1 0 1 0
0 1 0 1 0 1 0 1
1 0 1 0 1 0 1 0
0 1 0 1 0 1 0 1
1 0 1 0 1 0 1 0
0 1 0 1 0 1 0 1