Left-sorted Bongard Problems have the the keyword "right-narrow" on the OEBP.
This sorts Bongard Problems based on how BP513 (left-narrow) would sort them if they were flipped; see that page for a description.
Adjacent-numbered pages: BP509 BP510 BP511 BP512 BP513  *  BP515 BP516 BP517 BP518 BP519
dual, meta (see left/right), links, keyword, side
bp [smaller | same | bigger]
Aaron David Fairbanks