1. An educational apparatus for teaching phonics, spelling and reading, the apparatus comprising a plurality of structural units, each including a first face and at least one additional face, a 3-letter word indicia imprinted upon each of said first faces, one word to a face, wherein each of said 3-letter word indicia indicates a different word, a 3-letter word indicia printed on the at least one additional face of each of the plurality of structural units, wherein each 3-letter word indicia on each of the said first faces constitutes a first word member of an instructional word-pair of which instructional word-pair a second word member is located on a face of another of the plurality of structural objects, wherein each instructional word-pair comprises two 3-letter words differing by substitution of a single letter.