This is one of E.E. Cummings’ poems influenced by the imagist movement that paints a visual image with the words of the poem. The movement in turn was partially influenced by Japanese haiku that attempts to capture a single image in the poem and the feeling it conveys.
Combining the letters into a normal sentence, the poem can be read as either “loneliness (a leaf falls)” or “(a leaf falls) loneliness.” The image of the letters as arranged is one of a a single leaf falling as well, twisting side to side, flat and horizontal, before finally settling on the ground (the longest letter grouping is at the bottom, where the leaf would be lying down). You can also see some of the leaf twisting in the second stanza by alternating “af” and “fa” and alternating consonants with vowels.
Aside from the striking visual image itself, the poem reinforces the solitary image of loneliness by repeatedly emphasizing the concept of one. This poem is set in typewriter format, which makes the lowercase L look like the number 1. The first line breaks up a “l” and an “a,” both singular concepts. The last line of the second stanza is “ll” — one repeated. The third stanza has “one” for its second line and “l” for its third line. Finally, the last part of the poem can be read as “oneliness” since the “l” of loneliness is hidden at the beginning of the poem behind parentheses and forgotten.