Stanza theory and conventions
There are four overlapping ways of handling rhymes and stanzas in European poetry, although only the easiest one has any importance in classic English poetry. Three of these techniques are usually referred to by their Provençal name, for reasons that are unclear to anybody but some long-dead Occitanic scholar.
The first one is called coblas continuadas; in it, any set of rhymed endings is restricted to a single stanza and no other one; this means that any rhyming pattern is resumed in the next stanza with a different set and generally no reference to the preceding one. In a few words, each line of a stanza only rhymes with other lines within the same stanza. This is the common way of writing poems both in English and in most other modern European languages.
As virtually every rhymed English poem you can quickly think of falls into this category, the Present Author refrains from bugging you with one more example, and for that you should be grateful to Him for centuries to come.
The second technique is called coblas capcaudadas; with it, one or more rhymes are carried from one stanza to the following one, so that they affect two stanzas only and not the whole work.
The third and even rarer one, coblas unissonantis consists in keeping the exact same rhymes the exact same positions in all stanzas.
Last but not least, there is the rime en kyrielle technique, which consists in periodically repeating an entire line. It is to be noted that some of the forms we shall analyse sometimes do not fall precisely in any one of these groups, but they can usually be assimilated to them. Furthermore, two or more techniques can be combined in the same poem: a piece written entirely in rime en kyrielle would just be a silly repetition of the same thing, for example, so that the reoccurring verses are complemented by new ones which are connected to them according to one, or more, of the three other ways of arranging verses.
All this may seem complicated, but the practical cases will immediately show how elementary the underlying concepts are; what actually matters is understanding that these four basic techniques, applied according to the taste of the poet, produce the endless variety of classic verse, and that the theoretical attempts at classifying hundreds of different verse forms appear to be idle and vain when compared to the more general idea. The case of the ode, which immediately follows, is by far the most prominent.

• Coblas continuadas

Ode
Under this tattered flag are grouped an endless number of poems made of equal stanzas in coblas continuadas. Such a poem need not be always called an 'ode', and oftentimes it is not even referred to as a verse form in itself; the rules generally applied in its construction are:

1. Stanzas are rhymed as coblas continuadas (see above)
2. Each line must be rhymed with at least another line in the same stanza
3. Each stanza is a sequence of the same types of verses as the others, in the same order and with the same rhyme scheme

Rhyming couplet
The easiest, basest kind of coblas continuadas (and of verse in general) is the rhyming couplet. Dearly loved by rhymesters and pop singers of all ages, this metre has become so common so quickly it actually features an impressive amount of decent, good and even masterly pieces. It is impossible to track back this verse to its origins, which are certainly to be found in the transition of Latin from a quantitative to an inflected language, and maybe even before that (hints of rhyming can be seen in some perfectly classic hexameters), but it was certainly already obsolete when the first Romance poems we know were written; in spite of that, rhyming couplets enjoyed an unrivalled popularity in the late Middle Ages, when they became the metre of the French and English lai. A rhyming couplet is simply a pair of verses, usually of the same type, rhyming with each other; several of these units are arrayed, without necessarily having any logical or phonetic interruption in between. Perhaps the true masterpiece of the kind is Verlaine's 'Effet de nuit'.

English examples are found throughout all the history of British literature, from Chaucer to Eliot, and particularly in the most shallow Cavalier poets; Marlowe's translations of Ovid' Elegies are an example of a less deleterious use of the form.
Couplets are used in classic European poetry basically only in English and French; they are avoided in Italian because they sound somewhat sing-songy, and Provençal authors seemed to think of them as too primitive a device. No Spanish example is known to the Present Author, who, however, from the abysms of his ignorance in the field, cannot say whether any exist.
Starting from the middle of the 19^th century, an increasing number of authors wrote rhyming couplets composed of verses of arbitrary length; this form, of which the best examples are perhaps to be found in Ogden Nash's work, is not strictly a type of coblas continuadas anymore.

Song
This is merely the name given by most English authors to odes made mostly of, or to couplets made exclusively of, verses with an odd number of metrical syllables (which, as already stated in chapter one, sound sing-songy). Most rock and country lyrics fit in this definition as well.
This is the first prosody manual ever, and maybe the last, revealing this truth to the people.
Songs are fairly common, often treat of Springtime and/or love, and tend to be demented and annoying; songs, or fragments of them, are often included in Renaissance plays in a vain effort to wake up the onlooker: even the gloomiest Webster at times resorts to this childish device as in 'The Duchess of Malfi' (albeit he manages to be anamorphic even in that, and lengthening some verses and shortening others while keeping the general effect):

Epigram
Epigrams are not too clearly defined as a form; they have antique origins, being already common in decadent Latin authors, particularly Seneca and Martial. Through the influence of the latter author, epigrams were introduced in English as a type of short, rhymed metre used for trenchant humour, personal attacks, and/or triviality.
Prosodically speaking, epigrams generally are made of a single stanza, often a short one; as the original Latin ones are written in distichs, English ones tend to be either made of couplets of uniform verses, or of alternated patterns of one longer and one shorter verse.
An example of the former type is provided by Sir John Harrington's translation of Martial's 'To one that had meat ill dressed':

Whereas the latter type is well illustrated by the Earl of Rochester's 'On Charles II':

Famous epigrams were written by John Donne and Ben Jonson; the latter was quite prone to use this otherwise polemical form for toadying, as one can see in this example.

Ballad
As hinted above, the ballad is basically a barbaric involution of an ode with four lines in each stanza. The various degrees of the transition (Darwin, envy me!) are apparent in some of Robert Burns' works. Its verses usually have an easy but irregular rhythm, and they often either have eight metric syllables or four beats (or both features). The second line of each stanza rimes with the fourth, while the first and third are unrhymed (or rime with each other, but that is rare); the last one is sometimes shorter than the other three, carrying only three beats (or six metric syllables, or both).
Ballads are used for storytelling, usually for melancholic and corny tales about damsels and knights; well-crafted samples of this typically 18^th century form sound somewhat archaic, so that the layman uses to think it originated in mediaeval ages (during which, instead, the world 'unrhymed' was never applied to poetry by any sane man).
Ballads are exclusive to English and the Scottish (non Celtic) dialect; Coleridge was certainly thinking of them when writing his 'Rhyme of the Ancient Marineer', and Keats' 'La Belle Dame Sans Merci' is definitely an example.

• Coblas capifinidas

Terza Rima
Logically speaking, this form is the simplest possible application of the concept of coblas capifinidas: it is made by a sequence of stanzas of three verses each of the same type, of which the two extreme ones rhyme with each other, while the inner one rhymes with the first (and then also with the last) line of the next stanza, thus creating a pattern of the type:

Pantoum
Until now, in this chapter, we have mostly been frolicking around with forms one can easily use to write a list of his desiderata at the greengrocer's shop down the lane; the Present Author is actually able to do that in a pantoum as well (although He is keeping to his promise not to flaunt His skill and shan't do it here), but freely admits it takes some time and concentration.
The pantoum is a peculiarly abstruse classic Malay open form that has been introduced into French poetry by Hugo, through a translation in his 'Orientales'; the metre is so difficult that, up to today there is no example in classic literature that fits exactly in its definition, which is the following:

1. Each verse line must have eight syllables
2. A pantoum is made of stanzas of four lines each
3. The first line must rhyme with the fourth, and the second must rime with the third
4. The second line of each stanza must be used as the first line of the next stanza
5. The fourth line of each stanza must be used as the third line of the next stanza
6. The first line of the first stanza must be used as the last line of the last stanza

• A pantoum, most like a rondeau, is based on two rhyming groups only
• A pantoum has an odd number of stanzas
• A pantoum is damn hard to write properly

A piece in this style, and probably the most popular pantoum ever written, is Baudelaire's 'Harmonie du Soir' A more relaxed, and therefore more popular, convention rhymes the first line with the third and the second with the fourth, producing a completely different effect, but at least dramatically easying the execution to the scheme:

Albeit obviously a simplification, this second definition of pantoum is used by such poets as Banville and Laforgue and, in England, by Henry Austin Dobson, whose 'In Town' is a good example of the form. A quite widespread opinion in some (allegedly) English-speaking countries pretends pantoums are only a mean by which one can write a 'poem' of 2n+4 lines while squeezing only n+4 of them out of his miserable brains: we have too high an opinion of our Reader's tastes to irk him with examples of this kind.
Pantoums are used in Malay, French and English, usually for melancholy descriptive pieces; it is quite interesting to notice that the word 'pantum' in Malay doesn't indicate any form in particular, and just means 'poem'.

Virelai ancien
The virelai ancien is likely the most difficult form in coblas capifinidas ever devised. It is made of a sequence of 12-line stanzas; in each of these, lines 1, 2, 4, 5, 7, 8, 10 and 11 rime with each other and have eight metrical syllables; lines 3, 6, 9, and 12 rime with each other and have four metrical syllables. The pattern is therefore

One can go on like that as long as he wishes, but the shorter lines in the last stanza must rime with the longer ones in the first. The Present author is aware that this is a terrible mess, and sorry he is unable to provide you with any example, as he himself suspects none exists (although Chaucer's virelai is in coblas capifinidas and resembles our definition a bit), and that this metre is merely a speculation. Anyway, a virelai ancien, e.g., of five stanzas would have this structure:

• Coblas unissonantis

Troubadouric Song
The troubadouric song is perfectly alike to an ode, and follows the same rules with one difference: its stanzas are rhymed as coblas unissonantis rather than as coblas continuadas (refer to the first paragraph), although rhyming also within the same stanza is neither forbidden nor particularly rare; also, unlike the ode, this metre is almost invariably concluded by an envoi (by several of them, at times), which is built exactly as the other stanzas, but with a number of lines removed starting from the top (the examples will clarify this point better).
The term 'troubadouric song' is appropriate to the most common usage of this form in French and, mostly, Provençal, but it is not standard, and its definition as such is probably exclusive to this guide.
This type of metre was the most popular one among 'trobar clus' Provençal poets around the turn of the XII century, but has found applications in French in the same age and in Italian, although very seldom, in the late mediaeval age; the involvement of English in this form was triggered by T. S. Eliot, who shows interest for it in several works. Here are some examples:
Petrarca's 'Verdi panni, sanguigni, oscuri o persi'
'Ans que sim reston de branchas' by Arnaut Daniel
The second part of 'The Dry Salvages' quartet by T. S. Eliot
This form has been originally devised for courtly love songs, but it has occasionally been employed for lechery, war songs and political themes -- almost everything aside from descriptions.

• Rime en kyrielle:

Virelai nouveau
The virelai nouveau is among the rarest metres, and one of the most unclear in its definition; there certainly are French examples, and some authors seem convinced that English and Latin ones exist as well; it only shares the first part of the name with the virelai ancien, and it is an even more difficult to write.
This form starts with a couplet, ends with the same (sometimes turned upside-down), and is made of stanzas that use only two rhymes, ending alternately with one line of the starting couplet or the other. Banville's 'Virelai a mes editeurs' is a good example, and Tennyson is said to have written something in this style as well.
This as far as the theory goes; actual virelais generally appear as a disorderly sequences, in which the two rhymes of the first stanza are used alternately in the other ones, and the first line also concludes every even stanza, and the poem.
Probably, the most famous example is 'Je chante par couverture' by C. Pisan; a more confusing specimen is this one by Deschamps. The English poem that perhaps approaches most closely the French virelai is the short piece that concludes Chaucer's The Parliament of Foules. Of course, as said before, the many English villanelles can be regarded as virelais nouveaux as well.

Glose
A form of Spanish origin, the glose has found acceptance in Central and South America as well, but has never encountered much favour in other linguistic areas. It consists of two parts: a head made of a few verses (usually four), often written by someone different from the author of the rest of the piece and a tail made of as many stanzas as the verses in the head are. Each stanza is built as a normal ode's, but must end with the corresponding verse of the head: the first stanza ends with the first verse of the head, the second stanza with the second verse and so forth. There is no general rule concerning the construction of the stanzas, except that they must be in coblas continuadas. The rondeau redoublé is, clearly, a variety of this form, so the Voiture example given in the former chapter should do for a French example; an English one has been written by Porter Garnett on a quatrain by E. Fitzgerald, while Spanish glosas range from the mystical ones by Juana Inés de la Cruz to the modern 'Ritmos negros del Perú' by singer Nicomedes Santa Cruz.
'Glosa' roughly means 'explanation' in Spanish, so that this form is practically the long unfolding of a concept contained in the few lines of the head. The character of this poem is then usually religious or philosophical and the opening lines are usually deeply gnomic.
Another variation on the glose (actually, a proper one turned upside-down) is the sonnet redoublé, a sequence in which the opening lines of fourteen sonnets are combined, in order, to form a fifteenth; it was popular in Elizabethian times.