At North Farm 

Somewhere someone is traveling furiously toward you, 
At incredible speed, traveling day and night,
Through blizzards and desert heat, across torrents, through narrow passes.
But will he know where to find you,
Recognize you when he sees you,
Give you the thing he has for you?

Hardly anything grows here,
Yet the granaries are bursting with meal,
The sacks of meal piled to the rafters.
The streams run with sweetness, fattening fish;
Birds darken the sky. Is it enough
That the dish of milk is set out at night,
That we think of him sometimes,
Sometimes and always, with mixed feelings?

(John Ashbery)

I think the ‘idea’ expressed in a work of art is often of the form ‘a bunch of things not previously known to be related are related.’ One way to express an idea of this kind is to eloquently lay out one’s thesis re: these things and their relation. Another way to express an idea of this kind is to create a text that the reader can relate to each thing in the bunch of things with surprising ease. Take ‘At North Farm’, which is equally close to being a reversal of Yeats’ ‘Sailing to Byzantium’, being a retelling of Kafka’s ‘A Message from the Emperor’, being a description of waiting for Santa Claus (cf. leaving out milk) as a child (cf. having no agency + having your material needs super provided for in mysterious ways), being a description of waiting for love as an adult living in a city (cf. again having no agency + having your material needs super provided for in mysterious ways), and being a ‘the ambassadors’ style memento mori where the traveller is a grim ripper thing which you are hiding from amidst the worldly riches. And, relatedly, the poem also plays on all these shared structures between something being very habitual and something being super eschatological — with the glass of milk connecting to casually leaving out some milk for the street cats that come by at night or for your house cat, connecting to Santa Claus, connecting to folk-religion things of leaving out food to appease/distract spirits that might come during the night —, and the way that things done for the sake of some eschatological hope or fear end up sort of indistinguishable from normal minor daily habits after enough iterations of the eschatological thing not happening.