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

"Unwordable" does not just mean convoluted, that is, involving a long description. "Unwordable" also does not just mean hard. Unwordable Bongard Problems are instead those Bongard Problems whose solutions tend to occur to people nonverbally before verbally. The typical "unwordable" Bongard Problem solution is not too difficult to see, and may be easy to describe vaguely, but hard to pin down in language.

The solution title given on the OEBP for "unwordable" pages is often something vague and evocative, further elaborated on in the comments. For example, the title for BP524 is "Same objects are shown lined up in both 'universes' vs. the two 'universes' are not aligned." If someone said this, it would be clear they had seen the answer, even though this is not a clear description.

Bongard Problems have been sorted here based on how hard they are to put into words in English. (See keyword culture.) It may be interesting to consider whether or not the same choices would be made with respect to other languages.

Adjacent-numbered pages:
BP501 BP502 BP503 BP504 BP505  *  BP507 BP508 BP509 BP510 BP511

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

bp [smaller | same | bigger]

Aaron David Fairbanks

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

In a "spectrum" Bongard Problem, there is an evident way to assign each object a value (e.g. "size" or "number of holes"). Then, to determine whether an object fits left or right in the Bongard Problem, its value is compared with a fixed threshold value.

Spectra can be continuous or discrete.

A "spectrum" Bongard Problem is usually arbitrary, since there could be made many different versions of it with different choices of threshold value. However, sometimes a certain choice of threshold is particularly natural. For example, the threshold of 90 degrees in "acute vs. obtuse angles" does not come across as arbitrary. And in BP2, the spectrum of values ("size") is vague, so much that the fuzzy threshold, of about half the size of the bounding box, does not seem arbitrary.

A spectrum Bongard Problem may or may not have the following properties:

1) The values assigned to objects are precise.

2) The threshold value between the two sides is precise.

3) The threshold value is itself sorted on one of the two sides.

Each of the latter two typically only makes sense when the condition before it is true.

If a spectrum Bongard Problem obeys 1) and 2), then it will usually be precise.

For example:

"Angles less than 90° vs. angles greater than 90°" is "precise".

If a spectrum Bongard Problem obeys 1), 2), and 3), then it will usually be allsorted.

For example:

"Angles less than or equal to 90° vs. angles greater than 90°" is "allsorted".

Discrete spectra usually satisfy 1) but do not satisfy 2). In a discrete spectrum Bongard Problem, there isn't one unambiguous threshold value. Consider "2 or fewer holes vs. 3 or more holes". (Is the threshold 2? 3? 2.5?)

In an especially extreme kind of spectrum Bongard Problem, one side represents just a single value, just the threshold value. For example, "right angles vs. obtuse angles." In certain cases like this the threshold is an extreme value at the very boundary of the spectrum of possible values. For example, consider "no holes vs. one or more holes." Cases like this might not even be understood as two sides of a spectrum, but rather the absence versus presence of a property. (See the keyword notso.)

Even more extreme, in some Bongard Problems, each of the sides is a single value on a spectrum. For example, BP6 is "3 sides vs. 4 sides". We have not been labeling Bongard Problems like this with the keyword "spectrum".

After all, any Bongard Problem can be re-interpreted as a spectrum Bongard Problem, where the spectrum ranges from the extreme fitting left to the extreme of fitting right.

https://en.wikipedia.org/wiki/Total_order

See BP874 for the version sorting pictures of Bongard Problems (miniproblems) instead of links to pages on the OEBP.

Adjacent-numbered pages:
BP502 BP503 BP504 BP505 BP506  *  BP508 BP509 BP510 BP511 BP512

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

bp [smaller | same | bigger]
zoom in left (spectrum_bp)

Aaron David Fairbanks

Left-sorted BPs have the keyword "left-finite" in the OEBP.

How to distinguish between different examples depends on the Bongard Problem. For example, in BPs about little black dots, examples may be considered the same when they have the same number of dots in all the same positions.

Note that this is not just BP516 (right-finite) flipped.

"Left-finite" implies left-narrow.

See left-listable, which is about an infinite left side that can be organized into a neverending list versus infinite left side that cannot be organized into a neverending list.

"Left-finite" BPs are typically precise.

See BP1032 for a version that sorts images of Bongard Problems (miniproblems) instead of links, and which only sorts images of Bongard Problems about numbers.

Adjacent-numbered pages:
BP510 BP511 BP512 BP513 BP514  *  BP516 BP517 BP518 BP519 BP520

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

bp [smaller | same | bigger]
zoom in right (bp_infinite_left_examples)

Aaron David Fairbanks

Left-sorted BPs have the keyword "right-finite" in the OEBP.

BPs are sorted based on how BP515 (left-finite) would sort them were they flipped; see that page for a description.

"Right-finite" implies right-narrow.

See right-listable, which is about an infinite right side that can be organized into a neverending list versus infinite right side that cannot be organized into a neverending list.

"Right-finite" BPs are typically precise.

See BP1041 for a version that sorts images of Bongard Problems (miniproblems) instead of links, and which only sorts images of Bongard Problems about numbers.

Adjacent-numbered pages:
BP511 BP512 BP513 BP514 BP515  *  BP517 BP518 BP519 BP520 BP521

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

bp [smaller | same | bigger]
zoom in right (bp_infinite_right_examples )

Aaron David Fairbanks

This refers to all Bongard Problem solution ideas. No need to be a particularly well-made or well-defined Bongard Problem.

Adjacent-numbered pages:
BP536 BP537 BP538 BP539 BP540  *  BP542 BP543 BP544 BP545 BP546

notso, meta (see left/right), links, world, left-self, right-null, left-it, feedback

everything [smaller | same]
zoom in left (bp)

Aaron David Fairbanks

Adjacent-numbered pages:
BP537 BP538 BP539 BP540 BP541  *  BP543 BP544 BP545 BP546 BP547

notso, meta (see left/right), links, oebp, world, left-self, right-null, left-it, feedback

everything [smaller | same]
zoom in left (bppage)

Aaron David Fairbanks

All ideas and things, with no limits.

Adjacent-numbered pages:
BP539 BP540 BP541 BP542 BP543  *  BP545 BP546 BP547 BP548 BP549

notso, meta (see left/right), links, world, left-self, right-finite, right-full, left-null, left-it, feedback, experimental, funny

everything [smaller | same]
zoom in left (everything) | zoom in right (nothing)

Aaron David Fairbanks

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

If rotating an example about the center can change its sorting the BP is a left example here.

Note that BPs about relative rotation comparisons fit on the right side.

See BP872 for the version with pictures of Bongard Problems instead (miniproblems) of links to pages on the OEBP.

Bongard Problems tagged "rotate" are usually handed, since any rotation can be created by two reflections. Not necessarily, however, since the reflected step in between might not be sorted on either side by the Bongard Problem.

Adjacent-numbered pages:
BP548 BP549 BP550 BP551 BP552  *  BP554 BP555 BP556 BP557 BP558

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

visualbp [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