Originally posted on The Lotus of Fire:
Rules of Decima-
A decima is an early 10-line Spanish poetic form, with a distinct break after the first 4. It uses an 8-syllable line and has an unusual but characteristic rhyme scheme.
The decima must follow this rhyme pattern: A/B/B/A (pause) A/C/C/D/D/C and consists of ten lines of 8 syllables.