In terms of writing characteristics, which of the following poems is different from other three?

“Doppelgänger” by English poet James A. Lindon (1914-1979), “Dammit I’m Mad” by American comedian, actor, writer & director Demetri Martin (b.1973) and “Two Brief Views of Hell” by American poet Susan Stewart (b.1952) are palindrome poetry, while “The Raven” (1845) by American writer and poet Edgar Allen Poe (1809-1849) is a lipogram poem.

Lipogram is a kind of constrained writing in which a particular letter or group of letters is avoided. Poe's “The Raven” contains no Z, which is also noted for its musicality, stylized language and supernatural atmosphere. It tells of a distraught lover who is paid a visit by a mysterious raven that repeatedly speaks a single word "Nevermore" to further antagonize the lover.

Palindromic poems, also known as palindrome poetry or mirrored poetry, combine poetic form with line palindromes or mirror-image word-unit palindromes. “Doppelgänger” depicts a man entering his house one evening, only to see a shadowy figure staring at him and his wife. In the second half of the poem, the lines are reversed and we see the same scene from the perspective of the mysterious doppelgänger. “Dammit I’m Mad” is unique in that it is both a line palindrome and word palindrome, which not only reverses the order of the lines for the second half of the poem but also reverses the order of the letters within the lines. “Two Brief Views of Hell” depicts a journey into and back out of hell through the use of line palindrome.