The pattern in each stanza is where the second and fourth line of each verse is repeated as the first and third of the next. The pattern changes though for the last stanza to the first and third line are the second and fourth of the stanza above (penultimate). The last line is a repeat of the first starting line of the poem and the third line of the first is the second of the last.
For example, a four stanza poem would look like this ...
1234 2546 5768 7381 ... this can go on indefinitely, just as long as it loops back to the original stanza, in the final one! Can use rhyme or no rhyme, but it's up to you ...