16. THE DOUBLE-HEADED PUZZLE.
Cut a circular piece of wood as in the [cut] No. 1, and four others, like No. 2. The puzzle consists in getting them all into the cross-shaped slit, until they look like Fig. 3.
17. THE ROW OF HALFPENCE.
Place ten halfpence in a row on the table. Then take up one of them and place it on another, never in any case passing over more than a penny (that is to say, two halfpence). Repeat the operation until no halfpenny remains by itself in the row.