Repetition may also be modified by inversion of thematic material. Inversion of a theme is somewhat like holding a piece of music in front of a mirror. What first went up then goes down in inverted form. This allows similarity and variety simultaneously. A sequence requires at least two segments the original and the one restated at a different pitch level.
Most sequences contain no more than several notes.
And most usually move in one direction, either up or down. Also, sequences generally continue with the same interval distance between statements. Sometimes each has a temporary tonal center different from the preceding sequence. Most fall somewhere in the middle, however. A leap of a fifth or larger is usually approached from the direction opposite the skip, and left in the direction opposite the skip.