Answer: 8. Verbs
Explanation:
Iris Tiedt had invented this type of form in ''A New Poetry Form: The Diamante''.
This is what shape looks like with parts of speech from above.
Noun
Adjective-Adjective
Verb-Verb-Verb
Noun-Noun-Noun-Noun
Verb-Verb-Verb
Adjective-Adjective
Noun