Abstract: An apparatus for working on both sides of a flat workpiece includes a first support surface having a first axial line thereacross, a second support surface juxtaposed to and associated with the first support surface and having a second axial line thereacross which lies in a common plane with the first axial line, and a first carrying assembly operably connected to the first support surface in a manner to movably reciprocate along the first axial line and having a first extending arm which is laterally displaced from one side of the common plane and a second extending arm which is laterally displaced from another side of the common plane. A second carrying assembly is operably connected to the second support surface in a manner to movably reciprocate along the second axial line, wherein the second carrying assembly includes a workpiece removably mounted in a manner to position the workpiece in the common plane between the arms such that the arms extend about the workpiece.

Abstract: A teaching aid for piano and other keyed musical instruments. The device has switches electrically connected to a matrix array and mechanically linked to each key for detecting each key depression, an LED associated with each key for signalling the keys which should be played and an alphanumeric display for showing notes in literal and octave notation and for showing the student's position in a composition or exercise. The displays are connected in a matrix array and along with the key sensing switches are connected through interface circuitry to a microcomputer. The microcomputer stores a sequence of musical steps forming a composition and compares played notes to the stored sequence. When the compared notes and the depressed keys are identical, the student is signalled and the microcomputer advances to the next musical step. When there is an error, the microcomputer recycles the same musical step.