1. Apparatus for practicing a method for teaching physical arts and skills, such as, for example, dancing, which comprises: a. establishing the active image of a performing instructor in a virtual optical plane; b. simultaneously establishing in a similar virtual optical plane, the active performing image of a pupil imitating the action of the instructor; and c. placing both virtual images in position for direct simultaneous viewing by the pupil while performing, to enable the pupil to observe both images for instructive comparison, comprising, in combination, a photographic record of a main mirror in front of the performing instructor to show a front elevational mirror image of the instructor while performing; and an auxiliary mirror to be positioned to one side of a visual reproduction of said main mirror and image, to enable an observer, such as a pupil, to stand where he can see the main mirror image of said instructor, while also seeing his own performing image in the auxiliary mirror.