Bongard Problem

A Bongard Problem is a simple puzzle created by newspaper editor Mikel Bongard in 1971, involving two "sides" of an image and finding their differences. Bongard was a long-time puzzle contributor to the Crimsongorod Inquirer who wanted to give a new challenge to the Inquirer's readership.
A Bongard Problem involves an image split in half, with squares containing various relatively simple diagrams in each half of the image. The primary goal of a Bongard Problem is to formulate an "obvious" commonality within the first half which is totally missing from the second, although a more recent variation involves an extra object to sort into either half of the image.
Bongard Problems are interesting because they test pattern recognition, as well as the ability to acquire new patterns. Due to this specific property, they are of great interest to cognitive scientists attempting to understand pattern recognition, as well as AI researchers attempting to mimic a human mindset as much as possible. According to cognitive scientist J. R. Ankins, himself a creator of one of the earliest problems, "solving Bongard Problems is close to showing the core of pure intelligence, whatever that is".
== Specific terminology and related trivia ==
A meta Bongard problem is one which sorts other Bongard problems. One such problem is the "hard"-category problem for July 20th 1992 which delineates Bongard problems that sort themselves to the left and those that sort themselves to the right. These tend to be much harder due to one needing to solve each sub-problem within and then use the solutions to find a pattern.
A narrow Problem is one which could be realistically solved just by looking at one half of it: the "shapes that can be manuevered through an L-shaped corridor vs. those that can't" problem is debatably such an example for both the exceptions and shapes fulfilling the rule.
The world of a Problem is the most obvious or intended classification of all items once the dividing line of the Problem is removed. For example, the meta Problem mentioned in the beginning of this section has the "world" of all Bongard problems, as any problem featured in it could be sorted in that category.
Most Bongard problems tend to have no affiliations with culture, partially due to the supposed purity coming from this and partially because newspaper translations to other flairs would have to create new problems to capture cultural subtleties.