Teaching aid for practising spelling - includes clip-on letters with different fittings ensuring correct choice of letters

摘要

The teaching aid includes a board with a number of parallel horizontal grooves into which plates (7) may be fitted. A peg (4) and notch (10) ensures that the plates fit only one way. The plate has a central hub (8) with a radial hole (9), designed to receive a second plate (12) bearing a letter (13). A pupil is provided with the outer plates (13) and attempts to fit them onto base plates (7) which have already been positioned in the board by the teacher. The position of the hole (9) and a peg (15) on the letter plate (13) varies with each letter, so only the correct letters will fit.