Enclosed rhyme (or enclosing rhyme) is the rhyme scheme ABBA (that is, where the first and fourth lines, and the second and third lines rhyme).
Enclosed-rhyme quatrains are used in introverted quatrains, as in the first two stanzas of Petrarchan sonnets.
"Exposure", by Wilfred Owen,[2] also has an example of enclosed rhyme.
Each of the eight stanzas have the ABBA half rhyming sequence: