Heinrich Schenker stated, quite forcibly, that sequences do not exist--that the term could not "possibly apply to art," and that "the mere fact of its existence as a theoretical term does not lend it any credibility as a concept." Instead, he said that musical "...content is rooted in the voice-leading transformations and linear progressions whose unity allows no segmentation or names of segments." He therefore does not allow them any place in his theoretical system. My view is different: sequences are "things" in the sense common to all things--just because things have no intrinsic fixed autonomous identity separate from everything else doesn't mean that they don't exist. Rather, such is the nature of their existence. Sequences not only exist within the large voice-leading/harmonic structure but have their own subsidiary harmonic/voice-leading structures. They are basic patterns that can be realized in many different ways, and tend to appear as middleground elaboratory structures. Mozart's F major piano sonata, K.280/I, seems to me a good example of a movement that is, in a sort of tactile way, held together by a tissue of sequences. In this talk I focus on the three main sequences (one in two different forms), focusing on their internal structures, processes of diminution, and roles within the wider voice-leading/harmonic framework, as a step towards answering Schenker's objection to them.