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.

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 left-BP919 for the BPs the OEBP advises users upload left and right examples for in pairs.

Bongard Problems such that potential left examples can intuitively be put in bijection with potential right examples vs. other Bongard Problems.

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" problems (left-BP552), 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 left-BP919 for the BPs the OEBP advises users upload left and right examples for in pairs.

Bongard Problems such that potential left examples can be put in "natural" bijection with potential right examples vs. other Bongard Problems.