Java™ Puzzlers: Traps, Pitfalls, and Corner Cases

B. Notes on the Illusions

This appendix contains brief descriptions of the illusions that appear throughout the book. The descriptions are grouped loosely by category. Within each category, the order is roughly chronological.

Ambiguous Figures

An ambiguous figure is a drawing that can be seen in two or more ways, though not at the same time. One kind of ambiguous figure is a two-dimensional drawing that can be seen to represent one of several different three-dimensional figures. The Ambiguous Cube (page 67) can be seen in three ways: as a large cube with a small cubic region missing from one corner, as a small cube sitting inside a corner of a larger one, and as a large cube with a small cube protruding from one corner.

Another kind of ambiguous ...