sub pivot {
	my @src = @_;

	my $max_col = 0;
	$max_col < $#$_ and $max_col = $#$_ for @src;

	my @dest;
	for my $col (0..$max_col) {
		push @dest, [map {$src[$_][$col] // ''} (0..$#src)];
	}

	return @dest;
}