- Atari 2600: Pitfall (Internet Archive)
Pitfall! is a video game released by Activision for the Atari 2600 in 1982. It is the second best-selling game made for the Atari 2600 (after Pac-Man), with over 4 million copies sold.
- Axiom of choice (Wikipedia)
In mathematics, the axiom of choice, abbreviated AC or AoC, is an axiom of set theory equivalent to the statement that a Cartesian product of a collection of non-empty sets is non-empty. Informally put, the axiom of choice says that given any collection of sets, each containing at least one element, it is possible to construct a new set by choosing one element from each set, even if the collection is infinite.