vec($_[0], $_, 1) = $x for $s .. $SIZE * $t - 1;
vec($_[0], $_, $SIZE) = $x for $t .. $u - 1;
vec($_[0], $_, 1) = $x for $SIZE * $u .. $s + $l - 1;
vec($_[0], $_, 1) = $x for $s .. $SIZE * $t - 1;
vec($_[0], $_, $SIZE) = $x for $t .. $u - 1;
vec($_[0], $_, 1) = $x for $SIZE * $u .. $s + $l - 1;