$g = [];
$g[1][1] = 'g1';
$g[2][2] = 'g2';
$g[3][3] = 'g3';
$g[4][4] = 'g4';
$g[5][5] = 'g5';
$g[6][6] = 'g6';
$error = null;
$b = [];
$b[1] = 'b1';
$b[] = 'b2';
$b[] = 'b3';
$b[] = 'b4';
$b[] = 'b5';
$b[] = 'b6';
$error = null;
foreach ($g as $v1) {
foreach ($v1 as $num => $v2) {
echo $b[$num] . '-' . $v2 . PHP_EOL;
}
}