The cycle of fugues is introduced and concluded by a Praeludium and Postludium, the second formed by turning the Praeludium upside down and reading it backwards. In solving technical problems he posed himself, Hindemith created a work of considerable imagination. Intellectual achievement and sheer delight in playing are shown not to be mutually exclusive. The Ludus is a graphic example of the composer's delight in the fantastic. He illustrated the work with colored pencil, drawing a lion for each entry of the subject of the fugues. And for each of the twelve, a different kind of lion according to the character of the music, providing an instructive formal analysis of the music.