Ae freislighe (ay Fresh-lee)

Irish. Syllabic. As Irish and Welsh forms are complex systems of rhyme, alliteration, and consonance, they cannot be reproduced accurately in the English language. One can pay attention to only the rhyme scheme and syllabification. Thus, ae freislighe, simplified, is a Quatrain Stanza of seven syllable lines. Lines 1 and 3 rhyme in triple rhymes; lines 2 and 4 rhyme in double rhymes. The poem (not the stanza) should end with the same first syllable, word, or line with which it begins. The technical term for this ending is dunadh, and it occurs in all the Gaelic forms.
The diagram thus looks like this:

1 -- xxxx (xxa)
2 -- xxxxx(xb)
3 -- xxxx (xxa)
4 -- xxxxx(xb)

In simple words, it is an English accentual-syllabic Quintet Stanza that is followed by a special set of five lines that have the characterstics that make them known as 'Bob and Wheel'. The bob rhymes with lines (2) & (4) of the wheel; lines (1) & (3) of the wheel rhyme with each other.
The structure would look like this:
Line 1 -- ...xx xa (The bob can be an enjambed line that is continued and completed by the wheel.)
Line 2 -- xx xx xb
Line 3 -- xx xx xa
Line 3 -- xx xx xb
Line 4 -- xx xx xa
(These last 4 lines of the 5-lines stanza is called the 'wheel'.)

Carol

French and English. A joyous hymn. Originally it had a two-line burden or Texte Couplet, rhyming a1 a2, and any number of Quatrain stanzas, rhyming bbba The last lines of these stanzas rhymed with the burden lines. The lines are generally trimeter or tetrameter, with no set verse foot.
Example:

The Shepherd's Carol

Terly terlow, terly terlow,
Merry the shepherds began to blow!

About the field they piped full right,
Even about the midst of the night,
And down from heaven there came a light,
Terly terlow, terly terlow!

Of angels there came a company
With merry songs and melody;
The shepherds anon. did them espy --
Merry the shepherds began to blow!

.....

Didactics

Didactics is a minor subgenre of the literary genre called poetry. Didactic poetry is instructional (teaching poetry); its purpose is to give instructions or information regarding some subject. There are traditionally four didactic forms in English Literature.

The EPISTLE is a loose form, a letter to someone in particular or to mankind in general.

The PRIMER COUPLET, a set form, is a dipodic couplet, rhyming aa. Usually, primer couplets are rhymed aphorisms. Example:
Obadiah
Jumped in the fire,
Fire was hot,
He jumped in the pot,
The pot was so little
He jumped in the kettle,
The kettle was so black
He jumped in the crack.....

The RIDDLE is a short lyric that poses a question, the answer to which lies hidden in hints.

GEORGICS are rhymed instructions or directions in the arts, sciences, or trades -- versified handbooks. Example: David Wagoner's 'Staying Alive'.