Abstract: A keyboard apparatus includes a first key assembly, a second key assembly, and a third key assembly. The first key assembly includes a first key being slidably in contact with a first member at a first position and a second member at a second position. A first minimum distance between the first key assembly and the second key assembly at the rear ends thereof is larger than a second minimum distance between the first key assembly and the second key assembly at the second position within a range of rotation of the first key assembly. A third minimum distance between the first key assembly and the third key assembly at the rear ends thereof being larger than a fourth minimum distance between the first key assembly and the third key assembly at the second position within the range of rotation of the first key assembly.

Abstract: Musical note tiles, a system for teaching music notation and composition, and associated methods are disclosed. The system includes manipulative musical note tiles. The note tiles are transparent and adapted for use on measure plaques, or like surfaces. The note tiles can adhere to a surface with static cling in one embodiment. Alternatively, the note tiles can adhere to a surface with magnetism. The note tiles are mathematically proportionate to each other as they are to the relative lengths of sound durations represented by note icons. The measure plaques are in complete mathematical congruence to the lengths of the note tiles. The note tiles can include transparent texture strips. The system also includes mounting platforms, staff extension plaques, grand staff brace labels, bridges, spacer tiles, pre-reading tiles, and symbol labels.