For example, the poem begins: "Sithen the sege and the assaut was sesed at Troye" (line 1), with the "s" sound recurring five times within the single long line. The long lines do not rhyme with each other. However, they are organized in stanzas of fifteen to twenty-five lines, and each stanza concludes with a construction known as a "bob and wheel. " This term refers to a group of five short lines, which do rhyme, to the pattern of ababa. If you are not reading Gawain in the original Middle English, the poetic structure may not be maintained in the translation.
Some modern English translations keep the rhyme and meter strictly; others are only prose translations. SYMMETRY Sir Gawain and the Green Knight has a symmetrical structure. Everywhere in the poem is balance, contrast and antithesis. The poet highlights number symbolism to add symmetry and meaning to the poem. For example, three kisses are exchanged between Gawain and Bertilak's wife; Gawain is tempted by her on three separate days; Bertilak goes hunting three times, and the Green Knight swings at Gawain three times with his axe.
The number two also appears repeatedly, as in the two beheading scenes, two confession scenes, and two castles.  The five points of the pentangle, the poet adds, represent Gawain's virtues, for he is "faithful five ways and five times each".  The poet goes on to list the ways in which Gawain is virtuous: all five of his senses are without fault; his five fingers never fail him, and he always remembers the five wounds of Christ, as well as the five joys of the Virgin Mary. The fifth five is Gawain himself, who embodies the five moral virtues of the code of chivalry: "friendship, generosity, chastity, ourtesy, and piety".  All of these virtues reside, as the poet says, in the "Endless Knot" of the pentangle, which forever interlinks and is never broken. This intimate relationship between symbol and faith allows for rigorous allegorical interpretation, especially in the physical role that the shield plays in Gawain’s quest.  Thus, the poet makes Gawain the epitome of perfection in knighthood through number symbolism. The number five is also found in the structure of the poem itself. Sir Gawain is 101 stanzas long, traditionally organised into four 'Fitts' of 21, 24, 34, and 22 stanzas.
These divisions, however, have since been disputed; scholars have begun to believe that they are the work of the copyist and not of the poet. The original manuscript features a series of capital letters added after the fact by another scribe, and some scholars argue that these additions were an attempt to restore the original divisions. These letters divide the manuscript into nine parts. The first and last parts are 22 stanzas long. The second and second-to-last parts are only one stanza long, and the middle five parts are eleven stanzas long.
The number eleven is associated with transgression in other medieval literature (being one more than ten, a number associated with the Ten Commandments). Thus, this set of five elevens (55 stanzas) creates the perfect mix of transgression and incorruption, suggesting that Gawain is faultless in his faults. The format of “Sir Gawain and the Green Knight” works on the principles of repetition and multiplication. Think about the number of departures for adventure, the almost eerie property of “threes,” the characters who play multiple roles, the five points of the pentangle and so on.