What happens if you keep looking

On first looking at a drawing of this sort, you will probably immediately see a meaningful picture. Britannica Scholars: perception

After continued gazing, the initial percept may abruptly be replaced by another. Britannica Scholars: perception

Thereafter, the two percepts should alternate with the passage of time. Britannica Scholars: perception

Some people first see a vase, whereas others first see two profiles. Britannica Scholars: perception

The fluctuations of figure and ground may occur even without conscious effort. Britannica Scholars: illusion

Some studies have suggested that younger people tend to perceive these reversals more readily than do their elders. Britannica Scholars: illusion

Britannica Students puts it as a rule: young people see the reversals more readily than do those who are more mature. Britannica Students: illusion