This is a “square poem”: it can be read vertically (first word of each line, second word of each line, and so on) as well as horizontally.

“One of Carroll’s most remarkable poems, if indeed he wrote it, was first published by Trevor Wakefield in his Lewis Carroll Circular, No. 2 (November 1974). The poem is quoted in a letter to The Daily Express (January 1, 1964) by a writer who tells of a privately printed book titled Memoirs of Lady Ure. Lady Ure, it seems, quoted the poem as one that Carroll wrote for her brother. Wakefield says that no one has yet located a copy of Lady Ure’s Memoirs, but whether this is still true I do not know.”