AMBIGUOUS Puzzles (AMB) in which something appears impossible or ambiguous.

Landscape or Portrait? (19th century hand coloured engraving)

Many hidden profiles of the "Goodies" and "Baddies" of the Napoleonic Wars.(Hand coloured engraving. 19th century)

Bottle filled by the late Harry Eng.
Hardwood plug has a steel bolt through it and a deck of 52 cards. There is a padlock through the end of the bolt which is also larger than the bottle neck as is the monkey's fist knot (USA 1980s).

Pepsi can contains a golf ball.

Impossible dovetails by Fred Irvine (New Zealand 1980s)