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
Bongard Problems that are hard for humans to solve but easier for computers to solve vs. Bongard Problems that are hard for computers to solve but easier for humans to solve.