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

Right-sorted Bongard Problems have the keyword "less." They are not necessarily "bad," but we do not want more like them.

Adjacent-numbered pages:
BP498 BP499 BP500 BP501 BP502  *  BP504 BP505 BP506 BP507 BP508

subjective, meta (see left/right), links, keyword, oebp, right-finite, left-it, feedback, time

bp [smaller | same | bigger]

Aaron David Fairbanks

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

Right-sorted Bongard Problems have the keyword "finished" on the OEBP.

Users are not able to add or remove examples from Problems tagged "finished." (This is unusual; most Bongard Problems on the OEBP can be expanded indefinitely by users.)

A "finished" Bongard Problem will always admit the alternative, convoluted solution "is [left example 1] OR is [left example 2] OR . . . OR is [last left example] vs. is [right example 1] OR is [right example 2] OR . . . OR is [last right example]".

Bongard's original Problems are tagged "finished."

Adjacent-numbered pages:
BP499 BP500 BP501 BP502 BP503  *  BP505 BP506 BP507 BP508 BP509

meta (see left/right), links, keyword, oebp, presentationmatters, left-finite, right-finite, instruction

bppage [smaller | same | bigger]

Aaron David Fairbanks

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

Call a rule "narrow" if it is likely to be noticed in a large collection of examples, without any counterexamples provided.

A collection of triangles will be recognized as such; "triangles" is a narrow rule. A collection of non-triangular shapes will just be seen as "shapes"; "not triangles" is not narrow.

Intuitively, a narrow rule seems small in comparison to the space of other related possibilities. Narrow rules tend to be phrased positively ("is [property]"), while non-narrow rules opposite narrow rules tend to be phrased negatively ("is not [property]").

Both sides of a Bongard Problem can be narrow, e.g. BP6.

Even a rule and its conceptual opposite can be narrow, e.g. BP20.

A Bongard Problem such that one side is narrow and the other side is the non-narrow opposite reads as the narrow side being a subset of the other. See BP881.

What seems like a typical example depends on expectations. (See the keyword assumesfamiliarity for Bongard Problems that require the solver to go in with special expectations.)

A person might notice the absence of triangles in a collection of just polygons, because a triangle is such a typical example of a polygon. On the other hand, a person will probably not notice the absence of 174-gons in a collection of polygons.

Typically, any example fitting a narrow rule can be changed slightly to no longer fit. (This is not always the case, however. Consider the narrow rule "is approximately a triangle".) See the keyword stable.

It is possible for a rule to be "narrow" (communicable by a properly chosen collection of examples) but not clearly communicated by a particular collection of examples satisfying it, e.g., a collection of examples that is too small to communicate it.

Note that this is not just BP514 (right-narrow) flipped.

Is it possible for a rule to be such that some collections of examples do bring it to mind, but no collection of examples unambiguously communicates it as the intended rule? Perhaps there is some border case the rule excludes, but it is not clear whether the border case was intentionally left out. The border case's absence would likely become more conspicuous with more examples (assuming the collection of examples naturally brings this border case to mind).

See BP830 for a version with pictures of Bongard Problems (miniproblems) instead of links.

Adjacent-numbered pages:
BP508 BP509 BP510 BP511 BP512  *  BP514 BP515 BP516 BP517 BP518

dual, meta (see left/right), links, keyword, side

bp [smaller | same | bigger]

Aaron David Fairbanks

Left examples have the keyword "experimental" on the OEBP.

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

Experimental BPs push the boundaries of what makes Bongard Problems Bongard Problems.

Traditional BPs show some simple property of black and white pictures. The OEBP is a place with many wild and absurd Bongard Problems, so it is useful to have an easy way to just find the regular old Bongard Problems.

Adjacent-numbered pages:
BP545 BP546 BP547 BP548 BP549  *  BP551 BP552 BP553 BP554 BP555

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

bp [smaller | same | bigger]

Aaron David Fairbanks

Adjacent-numbered pages:
BP753 BP754 BP755 BP756 BP757  *  BP759 BP760 BP761 BP762 BP763

meta (see left/right), links, metaconcept

bp [smaller | same | bigger]

Harry E. Foundalis

See BP836 for the version with pictures of Bongard Problems instead of links to pages on the OEBP.

Adjacent-numbered pages:
BP755 BP756 BP757 BP758 BP759  *  BP761 BP762 BP763 BP764 BP765

meta (see left/right), links, metaconcept, primitive

bp [smaller | same | bigger]

Harry E. Foundalis

Alternatively, BP pages on the OEBP with number less than or equal to 100 vs. other BP pages.

Bongard's original Problems have the keyword "bongard" on the OEBP.

Adjacent-numbered pages:
BP793 BP794 BP795 BP796 BP797  *  BP799 BP800 BP801 BP802 BP803

meta (see left/right), links, keyword

bppage [smaller | same | bigger]

Aaron David Fairbanks

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

If applying a scaling along one particular axis to the whole of any example can change its sorting the BP fits on the left side here. (For BPs with bounding boxes this means scaling and cropping, but without cutting out any detail.)

Adjacent-numbered pages:
BP1107 BP1108 BP1109 BP1110 BP1111  *  BP1113 BP1114 BP1115 BP1116 BP1117

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

[smaller | same | bigger]

Leo Crabbe

Bongard Problems sorted left have the keyword "oebp" on the OEBP.

Most Bongard Problems relating to the OEBP are meta.

Adjacent-numbered pages:
BP1108 BP1109 BP1110 BP1111 BP1112  *  BP1114 BP1115 BP1116 BP1117 BP1118

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

Leo Crabbe

This classification is specifically concerned with changes to examples that leave them sortable, as there are almost always ways of adding details to a BP's examples that make them unsortable.

Right-sorted BPs in this Bongard Problem are often Bongard Problems where there is always a way of adding to left-sorted examples to make them right-sorted, but not the other way around, or vice versa.

Another version of this Bongard Problem could be made about adding white (erasure of detail) instead of black (addition of detail).

Another version could be made about adding either white or black, but not both.

Where appropriate, you can assume all images will have some room in a lip of white background around the border (ignoring https://en.wikipedia.org/wiki/Sorites_paradox ).

You can't expand the boundary of an image as you add detail to it. If image boundaries could be expanded, then any shape could be shrunken to a point in relation to the surrounding whiteness, which could then be filled in to make any other shape.

How should this treat cases in which just a few examples can't be added to at all (like an all-black box)? E.g. BP966. Should this be sorted right (should the one special case of a black box spoil it) or should it be sorted left (should examples that can't at all be further added be discounted)? Maybe we should only sort BPs in which all examples can be further added to. (See BP1143^left.) - Aaron David Fairbanks, Nov 12 2021

Is "addition of detail" context-dependent, or does it just mean any addition of blackness to the image? Say you have a points-and-lines Bongard Problem like BP1100, and you're trying to decide whether to sort it left or right here. You would just want to think about adding more points and lines to the picture. You don't want to get bogged down in thinking about whether black could be added to the image in a weird way so that a point gets turned into a line, or something. - Aaron David Fairbanks, Nov 13 2021

See BP1139 for Bongard Problems in which no example can be added to, period.

Adjacent-numbered pages:
BP1134 BP1135 BP1136 BP1137 BP1138  *  BP1140 BP1141 BP1142 BP1143 BP1144

meta (see left/right), links, sideless

Leo Crabbe