A category theory textbook opens the "motivation and use cases" section with the following poem: There's a tiresome young man in Bayshore. / When his fiance cr

A category theory textbook opens the "motivation and use cases" section with the following poem: There's a tiresome young man in Bayshore. / When his fiance cried 'I adore / the beautiful sea' / he replied 'I agree, / it's pretty, but what is it for?'