Thirteen words, and a whole change of weather inside a mind. A speaker's "small black thoughts" run into "the cold rain", and what follows is not misery but "joy of becoming one". The central idea is a surprising kind of relief. The self feels cramped and gloomy, and it is eased by dissolving into something larger and colder than itself, not by being comforted or cheered up.
The first line is built from four single-syllable words, so it reads slowly and heavily, with almost every word pressing down. "Small" and "black" are the poem's only descriptions of the thoughts, and they do a lot. "Small" suggests something shrunken, perhaps petty or hemmed in. "Black" gives it a mood, and also a look, like specks of ink or dark pellets. The thoughts are treated as physical objects, which is what lets them take part in the next line's action.
That action is "collide", the poem's only real verb of force. A collision is sudden and a little violent, and you might expect something painful to follow. The sound of the line prepares for it. The hard *k* in "black", "collide" and "cold" knocks against the *l* in "small", "collide" and "cold", so that the words seem to bump into one another as the thoughts do. The rain is "cold", and the poem does not warm it up to make the joy easier to accept. Nothing about the encounter is cosy, which makes the ending harder to predict and more convincing.
The third line is the turn, and it arrives with no warning. There is no punctuation anywhere in the poem, so "joy of becoming one" is not clearly attached to anything. It could describe the collision itself, or the speaker's feeling afterwards, or it could simply hang in the air as a separate fragment. That openness is useful. The joy seems to belong to the whole event, not to one person or one word. The rhythm helps. After the weighted first line, the unstressed syllables in "of be-" let line three move more quickly, and then it settles on "one", the last word and the last beat.
"One" is worth a second look. The poem begins with a plural, "thoughts", and a pair of things that meet, thoughts and rain. It ends on the smallest whole number. The movement from many separate things to a single thing is the poem's real plot. "Becoming" matters too, because it is a present participle. The merging is still going on and has not been completed, so the poem stops in the middle of the change, not after it.
There is no end rhyme, no regular pattern of syllables, and no title, only the three asterisks that mark the poem as untitled. The lines run roughly four, six and six syllables, so the poem has the compression of a haiku without its 5-7-5 count. It keeps the brevity but not the rules. With so little on the page, the white space around the lines matters. The reader has to supply the silence in which the thoughts fall and the rain keeps falling.
Many poems use the pathetic fallacy, where the weather mirrors the speaker's mood, so that gloomy feelings get gloomy skies. Here the mood and the weather match in colour and temperature, black and cold, but the poem does something more interesting with the match. Because the two are so alike, they can merge. Judging by the imagery, the speaker's sadness is not defeated by the rain. It is joined to it, and in that joining it stops being private. A reader could take this as relief from low spirits, or as a moment of letting go of the self, and the poem does not choose between these readings. Both fit the words.
That restraint is part of what makes the poem worth studying. It says something true about feeling bad, which is that the first step is often not to cheer up but to stop being alone with it. It also shows how much one well-placed word can do. "Joy" sits in a poem full of smallness, blackness and cold, and it stands out sharply. A student looking for an example of how little a poem needs, a single image, a single verb and a single surprise, could hardly find a cleaner one.