Discworld command help
octograve - Create an octogram.
octograve with <staff>
For some magical activities, it is necessary to have an octogram ready to act as a focus. This command lets you make such an octogram, for the cost of 50 magic points, with your favourite staff; the presence of a knob is optional.
> octograve with staff
You mark out the vertices of an octogram.
You begin to trace the octogram.
You finish tracing the octogram.
You grasp the old staff tightly and concentrate.
An octogram begins to glow on the floor.