One more solution won't hurt anyone.

sub transpose {
    my @t;
    for (my $i; $i<@_; $i++) {
        for (my $j; $j<@{$_[$i]}; $j++) {
            $t[$j][$i] = $_[$i][$j]
        }
    }
    wantarray ? @t : \@t
}

my @matrix = (
    [1, 2, 3, 4],
    [5, 6, 7, 8]
);

my @transposed = transpose (@matrix);
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