in the opening ritornello of bars (see above) the fugue subject is first heard in the harpsichord, then the violin and finally in the bass line, when it is accompanied for two bars by the first statement of the countersubject—a rising sequence of repeated notes and trills—in the harpsichord. this is followed by the first episode of bars in which motifs from the ritornello are developed between the upper parts in imitative responses and in parallel: rhythmic figures from the fugue subject are played in counterpoint to semiquaver passagework; and elsewhere the upper parts respond to each with trills. the ritornello then returns for seven bars with the fugue subject in the harpsichord. after the cadence, a pivotal two bar interlude introduces new motifs in all the parts: