Other "games" played in the music include posing puzzles of mode and "musica ficta" for the performers (e.g. the Kyrie of the "Missa Le serviteur" plays with the expectations of the very well known plainchant cantus firmus by setting up some knotty issues of the implied possibility of modal inflection with consistent extra flats.) The music is characteristically athletic in all voice parts, with the lower parts in particular featuring much that requires very fine singers, and not representing the normal simply harmonic function of the tenor-bass combinations used by most of his contemporaries. Often a highly elaborate set of quick motifs will spring unexpected from a previous slow-moving texture (e.g. the eruption of detailed duos beginning at "Glorificamus te" and climaxing at "Adoramus te" in the "Gloria" of the "Missa in myne zin").