the Chamber Secrets open news spread Hogwarts student petrify see basilisk Dumbledore got fire Harry try enter Chamber Secrets these are not good news Lord Voldemort the problem do not want anybody able enter chamber the Dark Lord go busy suck life GinnyThe Chamber Secrets nm rectangular grid cell column a light ray basilisk gaze pass column change direction but spell column magic reflect light ray gaze direction receive ray this show figure the left light ray pass regular column right ray magic column the basilisk locate right low right cell grid look leave direction lower left cell accord legend meet basilisk gaze directly die immediately but meet basilisk gaze column person petrify we know door Chamber locate leave upper left corner grid wants enter look direction movement direction upper right cell position this figure illustrate sample test give dimension chamber location regular column Lord Voldemort ask find minimum number column need magic want enter chamber petrify declare impossible secure chamber