All rhymes in a strophe can be linked by vowel harmony into one assonance. Second choir&colon; "At the gate of thy mercies" (etc., strophe of four verses). The ode generally has three parts&colon; a strophe, an antistrophe, and an epode. At the end of the refrain sung after the last strophe. The final strophe of 4 has an "accelerando" leading directly into the "vivace" of 5. The unit is the strophe, which may be the whole poem, or only a part. The term strophe is used in modern and post-modern criticism, to indicate "long non-isomorphic units". A simple form of Greek strophe is the Sapphic strophe. Usually there are three rhymes in the six-line strophe, but sometimes there are only two. Every strophe is complete in itself, and independent of the preceding strophe. Lowell later expanded it with a strophe to Lincoln. It has the nature of a reply and balances the effect of the strophe. To announce to females, it often mixes these whistles with a strophe of song. The strophe is obscure but may refer to some sort of religious ceremony.