sub interleave {
    return @{$_[0]} unless @{$_[1]};
    return @{$_[1]} unless @{$_[0]};
    return shift(@{$_[0]}), shift(@{$_[1]}), &interleave;
}


print interleave( ['a'..'e'], [1..5] ), "\n";
my %hash = interleave( ['a'..'e'], [1..5] );