#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my @ary = qw(red green brown);
my %hash = ();

eval '$hash{' . join('}{',@ary) . '}++;';

print Dumper(\%hash);

##</code><code>##

$VAR1 = {
          'red' => {
                     'green' => {
                                  'brown' => '1'
                                }
                   }
        };