Re:A monad is a monoid in the category of endofunctors, what...
by throwawaymath on Sunday February 10, 2019 @12:54PM
(#19128962)
To give credit where it's due, that diagram is from a /r/math thread: https://www.reddit.com/r/math/comments/99y547/my_digram_of_a...
For education, there is a happy medium between providing theoretical context and hand-waving over technicalities and learning by example.
Very nice diagram though.