The original form, in which there were sets of rhyming couplet, differs from the modern form, which changed over time when introduced to Europe. Victor Hugo is credited with introducing this poetic form to Europe.
The modern pantoum form can vary in length, but requires each stanza to be a quatrain. The second and fourth lines of each stanza are repeated in the following stanza, and in most circumstances, the first line of the pantoum is repeated in last line of the last stanza.
One exciting aspect of the pantoum is the subtle shifts of context as repeated phrases are revised with different punctuation.In John Ashbury's poem, "Pantoum", the line "Why the court, trapped in a silver storm, is dying." becomes, "Why, the court, trapped in a silver storm, is dying!" when repeated, reflecting the shift in emotion that can occur from a simple change of punctuation.