Perceptions of such objects remain stable for a time, then may flip, a phenomenon called multistable perception.
pɚsˈɛpʃənz ʌv sˈʌtʃ ˈɑːbdʒɛkts ɹᵻmˈeɪn stˈeɪbəl fɚɹə tˈaɪm, ðˈɛn mˈeɪ flˈɪp, ɐ fɪnˈɑːmɪnən kˈɔːld mˈʌltistəbəl pɚsˈɛpʃən.