Old woman, young woman
Do you see a young woman or and old woman?
If you see a young woman, and wish to see the old woman, imagine the ear as an eye, the necklace as a mouth and the chin as a nose.
If you see an old woman, and wish to see the young woman, imagine the eye as an ear, the mouth as a necklace and the nose as a chin.
Your brain wants to flip to either one or the other image but if you study it long enough you might see both images at once. Can you do it?