print "($.)\n";    # undefined
    $. = 10;
    print "($.)\n";    # 10, but for which file handle?
    print "ENTER: ";
    ''.<STDIN>;
    print "($.)\n";    # 1, for STDIN
    $. += 10;
    print "($.)\n";    # 11, still for STDIN
    print "ENTER: ";
    ''.<STDIN>;
    print "($.)\n";    # 12, not 2 !