# 5.5. Use prefixes to scope other logically different 
#      vars. For example, 'cgi_' to prefix vars holding 
#      params delivered via the cgi
my $cgi_foo = $cgi->param('foo');
my $cgi_bar = $cgi->param('bar');

# 6. Refs prefixed with the appropriate identifier. I wish 
#     Perl would extend the "different things look different" 
#     to enable easy identification of the kind of data 
#     structure a ref refers to.
my $aref_bar = foo(\@foo_bar);

# 7. Rules 1-5 apply to rule 6 as well... so, an array ref 
#    inside a sub would be $this_aref_bar, etc.