Fig. 21.––Set of Six Irregular Figures.
(6) Finally, there are four plain wooden tablets, i.e., without any geometrical inset, which should have no button fixed to them; also two other irregular geometrical figures. (Fig. 22.)
Fig. 22.––Set of Four Blanks and Two Irregular Figures.
Connected with this material there is a wooden 47 frame furnished with a kind of rack which opens like a lid, and serves, when shut, to keep firmly in place six of the insets which may be arranged on the bottom of the frame itself, entirely covering it. (Fig. 23.)
Fig. 23.––Frame to hold Geometrical Insets.