my $ar = [ [ 'HEAD_goes_here', 'BODY_here' ],
           [ 'FOOT', 'FOOT', 'FOOT', 'FOOT' ]
];

##</code><code>##

 my $scalars_flattened = [ \$ar->[0][0], \$ar->[0][1],
     \$ar->[1][0], \$ar->[1][1], \$ar->[1][2], \$ar->[1][3] ];  

##</code><code>##

 my @flat = @{$_[0]};
 while ( List::Util::any { 'ARRAY' eq ref $_ } @flat ) {
        @flat = map { 'ARRAY' eq ref $_ ? \(@$_) : \$_ } @flat;
        @flat = map { 'REF' eq ref $_   ? $$_    : $_ } @flat;
 }

##</code><code>##

 $ar = [ 'HEAD', 'BODY', [ 'FOOT', 'FOOT', 'FOOT', 'FOOT'], ];