27. An educational device as claimed in claim 26 wherein: said electronic devices of said medallions are switched "on" by simply opening the lids of said medallions; said electronic devices of said medallions are switched "off" by simply closing the lids of said medallions; said electronic devices of said medallions are powered by batteries mounted within said medallions.
27. An educational device as claimed in claim 26 wherein: said electronic devices of said medallions are switched "on" by simply opening the lids of said medallions; said electronic devices of said medallions are switched "off" by simply closing the lids of said medallions; said electronic devices of said medallions are powered by batteries mounted within said medallions. 28. An educational device as claimed in claim 27 wherein said electronic devices comprise: read-only-memories (ROMs) containing pre-programmed sets of said pairs of original indicia and secondary indicia; said read-only-memory can be incrementally addressed through manual activation of a pop-in-and-out switch, memory address being incremented by pushing said pop-in-and-out switch in the medallion and subsequently releasing said pop-in-and-out switch; output displays niched in said medallions, said output displays showing said pairs of said original indicia and said secondary indicia stored at current addresses of said read-only-memories.