J.S. Bach, Canone alla Settima - Var. 21 from the Goldberg Variations

Bach loves augmented triads. In his free counterpoint and in his chorales he will make sure the voices have no choice but to collide on this chord, to often hair-raising effect. In his later counterpoint he begins literally to build it into his strict canonical designs, as an integral feature. This fascinating, radical canon is one such example. His appetite for dissonance is extraordinary. Note also the enchanted Neapolitan sixth chord at the end, another favorite of his and which he invokes with pathos like no other composer.