Old woman...or young girl?
(hint: the old woman's nose is the young girls chin).

Man playing horn...or woman silhouette?
(hint: woman's right eye is the black speck in front of horn handle).

Woman in vanity...or skull?
(hint: move further a bit from the screen and blink to see the skull; looking at the mirror).

Two faces...or one?
(hint: two faces side profile; or one face front view).

A rabbit or a duck?
(hint: the duck is looking left, the rabbit is looking right)

A face of a native American...or an eskimo?

A book facing you, or turned away?