. . .
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
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Aaron David Fairbanks