You can build a simple color gradiant by doing something like:

my @to_color = qw/ one two three four five /;
my @colors = &get_gradients(scalar @to_color);

sub get_gradients {
   my $number   = shift;
   my $interval = 0xff / ($number - 1);
   my (@c, $i);

   push(@c, sprintf("%02x", $interval * $i++)) while $i < $number;
   return @c;
}
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Building an HTML table out of that information is left as an exercise for the reader. See CGI.