@coords = ( undef,           # use a null $coords[0]
            [13,9,6],          
            [184,9,6],
             ...
           );
for my $goal ( 1..100 ) {
    for my $well ( @existing_wells ) {
        my $img = ( $well == $goal ) 
                  ? $graph_links[$goal-1] 
                  : "array.bmp";
        my $coords = join ',', @{coords[$goal]};
        print qq(<area href="http://cgi-bin/$img" 
                 ALT="" shape="circle" 
                 coords="$coords">);
    }
}