Sounds very much sequential, even if very difficult:

> The performer's first reply is not an entire poem. Rather, the poem is created one line at a time. The first questioner speaks and the performer replies with one line. The second questioner then speaks and the performer replies with the previous first line and then a new line. The third questioner then speaks and performer gives his previous first and second lines and a new line and so on. That is, each questioner demands a new task or restriction, the previous tasks, the previous lines of the poem, and a new line.