David Lewin showed that the T/I (“T-eye”) group is dual to a dihedral group acting on these objects whose three generators form orbits of size 2, 6, 8, and 24. Secondary operations like the Slide and Nebendverwandt (-5[1])act on these objects and can be written as products of P, R, and L. Leonhard Euler visualized transformations on these objects with a hexagonal lattice diagram known as the Tonnetz that is studied in Neo-Riemannian theory. A functional analysis of these objects developed during the common practice period. These objects’ “quality” may be indicated with superscript symbols like a triangle or slashed circle. (10[1])Inversion changes the voicings of these objects, whose “progressions” are studied in harmony. (10[2])For 10 points, name these sets of three or more simultaneous notes that come in “major” and “minor” forms. ■END■ (10[1])