Hi, and welcome.

Well--there's the old trompe-l'oeil. This is really cutesy, but for all I know it'll fit the image you're trying to get across: peek-'n-seek. Hmm: A Different Angle? Acute Angle? Shell game? Slight of eye?

Ooh, this is cool, though I'm not recommending it as your title:
angle of extinction: the angle from its axis that a crystal must be rotated before appearing maximally dark when viewed in polarized light.

Can't come up with any others at the moment; will post or PM if I do.