Fig. 2
Fig. 3
When using a cord, instead of the wooden marking pin, it must be stretched tight on the centre pin, and the radius measured along it from the pin. The marker is then passed through the rope and bound in place with a piece of twine or soft wire. Care should be taken, when marking, that the rope rests either on the ground or parallel to it.
A circular bed is the easiest of all to set out, but it is the foundation of several others. The easiest are polygons of four, six, and eight sides. To lay out a four-sided polygon (Fig. 2), equal a square: Lay off the diagonal A B. Lay off C D at right angles to A B, and join A D, D B, B C, C A.
To lay out a six-sided bed (Fig. 3), equal a hexagon: From the centre C draw a circle with radius C 1. Then from 1 with the same radius cut the circle at 2, from 2 cut it at 3, and so on. Then join 1 2, 2 3, 3 4, etc. To lay out an eight-sided bed, equal an octagon (Fig. 4): Draw a circle, lay off the diameters A B, C D at right angles to each other. Next bisect the four right angles at E F G H, and join A E, E C, C G, G B, etc.
Fig. 4
Fig. 5