Is it a vase OR is it a silhouette drawing of two people facing one another?
Rubin's Vase | Danish psychologist Edgar Rubin introduced this illusion in his work 'Synsoplevede Figurer' ("Visual Figures") published around 1915.
It's actually Rubin's Vase, an optical illusion in which the negative space around the vase forms the silhouettes of two faces.
BTW, it's the most common optical illusions that use negative space .
