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

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

"Easy" means easy for human beings to solve, not computers.

Adjacent-numbered pages:
BP496 BP497 BP498 BP499 BP500  *  BP502 BP503 BP504 BP505 BP506

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

bp [smaller | same | bigger]

Aaron David Fairbanks

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

Right-sorted Bongard Problems have the keyword "less" on the OEBP. They are not necessarily "bad", but this keyword is used to exclude Bongard Problems from the "Solve" page on the website: https://oebp.org/solve.php

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

BPs sorted left are tagged with the keyword "abstract" on the OEBP. The solution is not an easily-checked or concretely-defined geometrical or numerical property in pictures.

Adjacent-numbered pages:
BP507 BP508 BP509 BP510 BP511  *  BP513 BP514 BP515 BP516 BP517

abstract, meta (see left/right), links, keyword, left-self, sideless

bp [smaller | same | bigger]

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 is the keyword "dual" on the OEBP.

Given an example there is some way to "flip sides" by altering it. The left-to-right and right-to-left transformations should be inverses.

It is not required that there only be one such transformation. For example, for many handed Bongard Problem, flipping an example over any axis will reliably switch its sorting.

It is not required that every left example must have its corresponding right example uploaded on the OEBP nor vice versa. See the keyword contributepairs for the BPs the OEBP advises users upload left and right examples for in pairs.

Adjacent-numbered pages:
BP529 BP530 BP531 BP532 BP533  *  BP535 BP536 BP537 BP538 BP539

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

bp [smaller | same | bigger]

Aaron David Fairbanks

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

See updown.

All "leftright" Bongard Problems are handed.

Adjacent-numbered pages:
BP530 BP531 BP532 BP533 BP534  *  BP536 BP537 BP538 BP539 BP540

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

handed_visualbp [smaller | same | bigger]

Aaron David Fairbanks

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

Meta Bongard Problems are Bongard Problems that sort Bongard Problems. Sometimes abbreviated MBPs.

The first meta Bongard Problem was BP200.

Some meta BP pages sort images of Bongard Problems (keyword miniproblems), while other meta BP pages sort other BP pages (keyword links).

BPs that sort meta-BPs are labelled metameta.

Adjacent-numbered pages:
BP532 BP533 BP534 BP535 BP536  *  BP538 BP539 BP540 BP541 BP542

meta (see left/right), links, keyword, world, left-self, sideless, metameta, left-full, feedback

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

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 "handed" on the OEBP.

If mirroring any example along the any axis can change its sorting the BP is "handed."

Note that BPs about comparing orientation between multiple things in one example fit on the right side.

See BP871 for the version with pictures of Bongard Problems (miniproblems) instead of links to pages on the OEBP.

The keyword leftright is specifically about flipping over the vertical axis, while the keyword updown is specifically about flipping over the horizontal axis.

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:
BP547 BP548 BP549 BP550 BP551  *  BP553 BP554 BP555 BP556 BP557

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

visualbp [smaller | same | bigger]
zoom in left (handed_visualbp)

Aaron David Fairbanks