In his new composition for oboe and harpsichord, Enjott Schneider deals with the 'circulus vitiosus', the vicious circle. The 'circulus' describes a fast whirling circular motion in rondo form which incorporates certain musicological diabolic features such as the tritone ('diabolus in musica'), sliding chromaticism and 'Devil’s trills'. The soloist is free to extend his own diabolesque fantasies further in a cadenza (ad lib.). The work can also be performed with piano or organ accompaniment.