This is the "smallest" possible valid Bongard Problem on black and white bitmap images (up to switching sides).

Adjacent-numbered pages:
BP854 BP855 BP856 BP857 BP858  *  BP860 BP861 BP862 BP863 BP864

minimal, blackwhite, perfect, pixelperfect, experimental, funny, unstableworld

black_or_white_pixel [smaller | same | bigger]
zoom in left (black_pixel) | zoom in right (white_pixel)

Aaron David Fairbanks

This is a generalisation of BP861.

Adjacent-numbered pages:
BP855 BP856 BP857 BP858 BP859  *  BP861 BP862 BP863 BP864 BP865

hard, nice, stub, precise, stretch, unstable, hardsort, challenge, creativeexamples, perfect, pixelperfect

fill_shape [smaller | same | bigger]

Leo Crabbe

See BP860 for the more general version of this solution.

Adjacent-numbered pages:
BP856 BP857 BP858 BP859 BP860  *  BP862 BP863 BP864 BP865 BP866

nice, precise, unstable, perfect, pixelperfect

fill_shape [smaller | same | bigger]

Leo Crabbe

Adjacent-numbered pages:
BP857 BP858 BP859 BP860 BP861  *  BP863 BP864 BP865 BP866 BP867

less, teach, anticomputer, culture, experimental

black_and_white_photograph [smaller | same | bigger]
zoom in left (black_and_white_face_photograph)

Leo Crabbe

Adjacent-numbered pages:
BP858 BP859 BP860 BP861 BP862  *  BP864 BP865 BP866 BP867 BP868

nice, precise, allsorted, math, hardsort, creativeexamples, unorderedpair

2_shapes [smaller | same | bigger]

Leo Crabbe

Right examples have the keyword "hardsort" on the OEBP.

Contrast "hardsort" to infodense, where examples have a high amount of information, but perhaps after parsing all the information in the examples it is easy to sort them.

BPs labelled "hardsort" are likely to be labelled hard, but perhaps not--e.g. in BP323 the answer is easy to guess, but laborious to verify.

Adjacent-numbered pages:
BP859 BP860 BP861 BP862 BP863  *  BP865 BP866 BP867 BP868 BP869

subjective, meta (see left/right), links, keyword

bp [smaller | same | bigger]

Aaron David Fairbanks

Left examples have keyword "distractingworld" on the OEBP.

This is different than the kind of distraction mentioned at noisy, which means there are details that are irrelevant to the solution changing between examples.

To label a BP "distractingworld" is to judge that the type of examples are more specific than should have been necessary to communicate the same general solution idea--this involves separating out which ideas are the nice ideas the BP really ought to have been about, and which ideas seem unimportant and irrelevant. On the other hand, to label a BP "noisy" is just to notice there are extra properties varying that are independent of the solution property.

Distractingworld BPs are often arbitrary.

Adjacent-numbered pages:
BP860 BP861 BP862 BP863 BP864  *  BP866 BP867 BP868 BP869 BP870

BP1105 was created as an extreme example of this. All images in that BP show the same distractingly detailed background, irrelevant to the solution.

stub, fuzzy, abstract, subjective, meta (see left/right), links, keyword

bp [smaller | same | bigger]

Aaron David Fairbanks

Left-sorted Bongard Problems have the keyword "creativeexamples" on the OEBP.

Be encouraged to contribute new interesting examples to Bongard Problems with this keyword.

There is much overlap with the keyword hardsort.

This is what it usually means to say examples fit on (e.g.) the left of a Bongard Problem in various creative ways: there is no (obvious) general method to determine a left-fitting example fits left.

There is a related idea in computability theory: a "non recursively enumerable" property is one that cannot in general be checked by a computer algorithm.

But keep in mind the tag "creativeexamples" is supposed to mean something less formal. For example, it requires no ingenuity for a human being to check when a simple shape is convex or concave (so BP4 is not labelled "creativeexamples"). However, it is not as if we use an algorithm to do this, like a computer. (It is not even clear what an "algorithm" would mean in this context, since it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

Adjacent-numbered pages:
BP861 BP862 BP863 BP864 BP865  *  BP867 BP868 BP869 BP870 BP871

notso, meta (see left/right), links, keyword

bp [smaller | same | bigger]

Aaron David Fairbanks

Left-sorted BPs have the keyword "notso" on the OEBP.

This meta Bongard Problem is about Bongard Problems featuring two rules that are conceptual opposites.

Sometimes both sides could be seen as the "not" side: consider, for example, two definitions of the same Bongard Problem, "shape has hole vs. does not" and "shape is not filled vs. is". It is possible (albeit perhaps unnatural) to phrase the solution either way when the left and right sides partition all possible relevant examples cleanly into two groups (see the allsorted keyword).

When one property is "positive-seeming" and its opposite is "negative-seeming", it usually means the positive property would be recognized without counter-examples (e.g. a collection of triangles will be seen as such), while the negative property wouldn't be recognized without counter-examples (e.g. a collection of "non-triangle shapes" will just be interpreted as "shapes" unless triangles are shown opposite them).

BP513 (keyword left-narrow) is about Bongard Problems whose left side can be recognized without the right side. When a Bongard Problem is left-narrow and not "right-narrow that usually makes the property on the left seem positive and the property on the right seem negative.

The OEBP by convention has preferred the "positive-seeming" property (when there is one) to be on the left side.

All in all, the keyword "notso" should mean:

1) If the Bongard Problem is "narrow" on at least one side, then it is left-narrow.

2) The right side is the conceptual negation of the left side.

If a Bongard Problem's solution is "[Property A] vs. not so", the "not so" side is everything without [Property A] within some suitable context. A Bongard Problem "triangles vs. not so" might only include simple shapes as non-triangles; it need not include images of boats as non-triangles. It is not necessary for all the kitchen sink to be thrown on the "not so" side (although it is here).

See BP1001 for a version sorting pictures of Bongard Problems (miniproblems) instead of links to pages on the OEBP. (This version is a little different. In BP1001, the kitchen sink of all other possible images is always included on the right "not so" side, rather than a context-dependent conceptual negation.)

Contrast keyword viceversa.

"[Property A] vs. not so" Bongard Problems are often allsorted, meaning they sort all relevant examples--but not always, because sometimes there exist ambiguous border cases, unclear whether they fit [Property A] or not.

Adjacent-numbered pages:
BP862 BP863 BP864 BP865 BP866  *  BP868 BP869 BP870 BP871 BP872

notso, meta (see left/right), links, keyword, left-self, funny

everything [smaller | same]
zoom in left

Aaron David Fairbanks

This fits on its own left side.

See BP821 for the version with links to pages on the OEBP (instead of images of Bongard Problems), of which this fits on the left side.

Adjacent-numbered pages:
BP863 BP864 BP865 BP866 BP867  *  BP869 BP870 BP871 BP872 BP873

notso, meta (see left/right), miniproblems, example, left-finite, left-full, impossible, experimental, funny, presentationinvariant

bpimage [smaller | same | bigger]

Aaron David Fairbanks