sestina
six stanzas of six lines
end
words impose a pattern
repeated in a strict order
that varies
1, 2, 3, 4, 5, 6
6, 1, 5, 2, 4, 3
3, 6, 4, 1, 2, 5
5, 3, 2, 6, 1, 4
4, 5, 1, 3, 6, 2
2, 4, 6, 5, 3, 1
5, 3, 1
a tercet serves as envoy
to include 2, 4, 6
bury those words internally