what symbols symbolises theme of Idividualism in this novel?

There are many symbols in the novel, but the symbol I most closely attribute to individuality would be the masquerade party. The party itself symbolizes the end of Nora's marital masquerade; her costume symbolizes the illusion of romance she's presented as a wife.

Another symbol, also to do with clothing is Nora's changing into regular clothes. This act is a symbol of her shedding the illusion of her marriage, and her acceptance of her own identity.