. . .
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
Every example is an image of a Bongard Problem, without bounding boxes around examples, with three examples on either side.
BP575 is similar.
Adjacent-numbered pages: BP195 BP196 BP197 BP198 BP199  *  BP201 BP202 BP203 BP204 BP205
nice, meta (see left/right), miniproblems, creativeexamples, assumesfamiliarity, structure, experimental, presentationinvariant
no_box_bpimage_three_drawings_per_side [smaller | same | bigger]
Harry E. Foundalis