Koan – A paradoxical anecdote or riddle, used in Zen Buddhism to demonstrate the inadequacy of logical reasoning and to provoke enlightenment.
A story about a Zen master and his student, sometimes like a riddle, other times like a fable, which has become an object of Zen study, and which, when meditated upon, may unlock mechanisms in the Zen student’s mind leading to satori; A riddle with no solution, used to provoke reflection on the … en.wiktionary.org/wiki/koan
One way to learn programming languages is through koans, learning through koans are now widespread and is made possible mostly because of unit testing. Through these koans, one can learn the programming language, its application and best practices.
Here is a list of Programming Languages and their koans.
The last two in the list are not Programming Languages are are still good koans for those who wish to learn them.