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 alternate, 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 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

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

Right-sorted BPs have the keyword "gap" on the OEBP.

A Bongard Problem with a gap showcases two completely separate classes of objects.

For example, the Bongard Problem "white vs. black" (BP962) has a gap; there is no obvious choice of shared context between the two sides. One could imagine there is a spectrum of grays between them, or that there is a space of partially filled black-and-white images between them, or any number of other ambient contexts.

Bongard Problems about comparing quantities on a spectrum should not usually be considered "gap" BPs. (Discrete spectra perhaps.) A spectrum establishes a shared context, with examples on both sides of the BP landing somewhere on it. (However, if it is reasonable to imagine getting the solution without noticing a spectrum in between, it could be a gap, since the ambient context is unclear.)

Bongard Problems with gaps may seem particularly arbitrary when the two classes of objects are particularly unrelated.

If a Bongard Problem has a "gap" it is likely precise: it will likely be clear on which side any potential example fits.

"Gap" implies stable. (This technically includes cases in which ALL small changes make certain examples no longer fit in with the Bongard Problem, as is sometimes the case in "gap" BPs. See also BP1144.)

See also preciseworld. "Gap" Bongard Problems would be tagged "preciseworld" when the two classes of objects are each clear; it is then apparent that there is no larger shared context and that no other types of objects besides the two types would be sorted by the Bongard Problem.

See BP1140, which is about any (perhaps large) additions instead of repeated small changes.

Adjacent-numbered pages:
BP959 BP960 BP961 BP962 BP963  *  BP965 BP966 BP967 BP968 BP969

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

Aaron David Fairbanks

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.

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

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

All of Bongard's original Problems have whitespace around the border of all examples.

Adjacent-numbered pages:
BP1191 BP1192 BP1193 BP1194 BP1195  *  BP1197 BP1198 BP1199 BP1200 BP1201

meta (see left/right), links, keyword

Aaron David Fairbanks

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

Bongard's original Problems never involved shades of gray. They were just black and white drawings.

Adjacent-numbered pages:
BP1193 BP1194 BP1195 BP1196 BP1197  *  BP1199 BP1200 BP1201 BP1202 BP1203

meta (see left/right), links, keyword

Aaron David Fairbanks