21. An educational device as claimed in claim 15 wherein: said sets of external indicia are on the first side of thin labels; said sets of upper-internal indicia are on the second side of said thin labels; said medallions comprise external magnifying glasses permanently mounted on the external side thereof, said medallions comprise internal magnifying glasses permanently mounted on the internal movable side thereof; said thin labels can be inserted between said magnifying glasses, said external magnifying glasses showing enlarged external indicia, said internal magnifying glasses showing enlarged upper-internal indicia.
21. An educational device as claimed in claim 15 wherein: said sets of external indicia are on the first side of thin labels; said sets of upper-internal indicia are on the second side of said thin labels; said medallions comprise external magnifying glasses permanently mounted on the external side thereof, said medallions comprise internal magnifying glasses permanently mounted on the internal movable side thereof; said thin labels can be inserted between said magnifying glasses, said external magnifying glasses showing enlarged external indicia, said internal magnifying glasses showing enlarged upper-internal indicia. 24. An educational device as claimed in claim 21, wherein: said first sets of external indicia and upper-internal indicia of said medallions of said rings on said fingers represent objects whose names begin with a letter corresponding to the key of the keyboard to be struck by said finger of said left hand; said second sets of external and upper-internal indicia of said medallions of said rings on said fingers represent objects whose names begin with a letter corresponding to the key of the keyboard to be struck by said finger of said right hand.