Not all visual Bongard Problems whose examples all have some amount of black in them are sorted left. In left-sorted BPs, there must be some concrete percentage of black that is exceeded by every sorted example.

Adjacent-numbered pages:
BP1161 BP1162 BP1163 BP1164 BP1165  *  BP1167 BP1168 BP1169 BP1170 BP1171

meta (see left/right), links

Leo Crabbe

Left-sorted Problems often have a specific format or deal with specific geometric shapes.

Almost any Problem that sorts the all-white or all-black panels will be sorted right.

Adjacent-numbered pages:
BP1159 BP1160 BP1161 BP1162 BP1163  *  BP1165 BP1166 BP1167 BP1168 BP1169

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

visualbp [smaller | same | bigger]

Leo Crabbe

Note that most traditional Bongard Problems don't sort an all black-panel at all.

See BP567 (left-null versus right-null) for the version about all-white panels, which is more often applicable.

Adjacent-numbered pages:
BP1155 BP1156 BP1157 BP1158 BP1159  *  BP1161 BP1162 BP1163 BP1164 BP1165

meta (see left/right), links, side, testexample

Leo Crabbe

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

Right-sorted Bongard Problems have the keyword "right-couldbe".

In a "couldbe" Bongard Problem, some relevant information is left out by the way objects are displayed. Solutions to "left-couldbe" BPs sound like "Could be a ___ vs. definitely not a ___" (and vice versa for "right-couldbe" BPs.)

To put it in mathematical jargon, there is a "projection" function from objects to pictures, such that objects satisfying property X are mapped to the same picture as objects not satisfying property X. Sorted on the "couldbe" side is the image (under projection) of the collection of objects satisfying property X.

Furthermore, usually X is a relatively narrow criterion, so that most objects do not satisfy it (see keywords left-narrow and right-narrow), and all pictures are in the image (under projection) of the collection of objects not satisfying property X.

Consider BP525, "Cropped image of a circle vs. not so." None of the left-hand examples are definitely an image of a circle, but they fit left because nothing indicates that they are not an image of a circle. A more pedantic solution to this Bongard Problem would be "There is a way of cropping a circle that gives this image vs. there isn't."

See also the keyword seemslike, where neither side can be confirmed.

Either "left-couldbe" or "right-couldbe" implies notso.

Although the descriptions of "left-couldbe" and "right-couldbe" sound similar to left-unknowable and right-unknowable, they are not the same. It is the difference between a clear absence of information and perpetual uncertainty about whether there is more information to be found.

"Left-couldbe" is usually left-narrow and "right-couldbe" usually right-narrow.

Adjacent-numbered pages:
BP1154 BP1155 BP1156 BP1157 BP1158  *  BP1160 BP1161 BP1162 BP1163 BP1164

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

Leo Crabbe

This Problem is mostly concerned with categorising BPs whose examples aren't necessarily formatted as traditional Bongard Problems.

Adjacent-numbered pages:
BP1149 BP1150 BP1151 BP1152 BP1153  *  BP1155 BP1156 BP1157 BP1158 BP1159

meta (see left/right), links

visualbp [smaller | same | bigger]

Leo Crabbe

This is a generalisation of Bongard Problems that allows them to have any number of sides. There is a sense in which this problem is about valid vs. invalid ways of partitioning a set of examples into equivalence classes.

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

Adjacent-numbered pages:
BP1148 BP1149 BP1150 BP1151 BP1152  *  BP1154 BP1155 BP1156 BP1157 BP1158

abstract, teach, meta (see left/right), miniproblems, infodense, structure, rules, miniworlds

zoom in left

Leo Crabbe

Left-sorted problems have the keyword "finishedexamples" on the OEBP.

The addition does not have to be slight.

Left-sorted Problems usually have a very specific collection of examples, where the only images sorted all show the same type of object.

Any Bongard Problem where all examples are one shape outline will be sorted left, and (almost) any Bongard Problem where all examples are one fill shape will be sorted right.

See BP1144 for the version about both additions and erasures, and only slight changes are considered.

See BP1167 for a stricter version, the condition that all examples have the same amount of black and white.

Adjacent-numbered pages:
BP1137 BP1138 BP1139 BP1140 BP1141  *  BP1143 BP1144 BP1145 BP1146 BP1147

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

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.

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.

Closely related to gap Problems and stable Problems.

Bongard Problems tagged finishedexamples will fit right.

Adjacent-numbered pages:
BP1135 BP1136 BP1137 BP1138 BP1139  *  BP1141 BP1142 BP1143 BP1144 BP1145

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

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

Adjacent-numbered pages:
BP1129 BP1130 BP1131 BP1132 BP1133  *  BP1135 BP1136 BP1137 BP1138 BP1139

meta (see left/right), links, metaconcept

bp [smaller | same | bigger]

Leo Crabbe