Amongst the many speculations that have from time to time been made regarding the origin and significance of the design on the Knossian coins, the suggestion was made by a contributor to _Knowledge_ about thirty years ago--somewhat similar theories having been expounded by a German writer a decade earlier--that this figure was a simplified diagram comparable with the diagrams described above. According to this conception the figure was intended as a clue to the actual labyrinth, the designs on the coins being perhaps copied from those on "souvenir" tokens issued by the priests or curators of the edifice, and indicated the right path to be taken, all other paths being omitted. By splitting the circular dividing walls so as to form a passage of the same width as the path shown in the figure, a maze of much more intricate appearance was arrived at, which, it was thought, might bear some resemblance to the form of the original labyrinth. [Illustration: FIG. 136.--Straight-line Diagram, Hampton Court Maze.] [Illustration: FIG. 137.--Straight-line Diagram, Hatfield Maze.] On the other hand, Dr. E. Krause, in a book of about the same date, showed how the Knossian design and certain other unicursal figures might be derived from a series of concentric circles, with interruptions along a radial line like the figures in the northern rock engravings described in Chapter XVII, by means of one or two simple methods of cross-connection (Figs. 138 and 139). Such speculations give food for thought, but we must remember that so far they _are_ speculations and not statements of fact. The use of the straight-line diagrams suggested above may be found helpful not only as a means of facilitating the study of an existing labyrinth, but also to some extent in designing a new one. It is not necessary to describe here in detail how to design a maze: "It is purely a matter of skill, Which all may attain if they will," and, like most tasks requiring simply common-sense, patience, and practice, it is much more trouble to explain than to perform. As regards the design of hedge mazes, the fact that the circumstances are hardly ever alike in any two actual cases gives plenty of scope for individuality and ingenuity. The space allowed may be strictly limited, or it may be of an awkward shape. The materials available for the walls may vary widely in character according to the space they require for their proper growth and maintenance, and thus affect the amount of path-area. [Illustration: FIGS. 138 and 139.--Derivation of Labyrinth Types from Rock-engraving Figures. (After Krause.)]