Instead of producing influence diagrams as we have described above, we may instead produce canonical wheel influence diagrams. These are the same as the influence diagrams described above (and share the properties of being influence diagrams in the classical sense) except that the shading of nodes is more detailed and has a different meaning. A simple switch, using the wheel control, determines whether the diagrams you produce have standard shading or canonical wheel shading. By default, all influence diagrams are of the standard variety. Other relevent controls are as follows. Node shading colours are controlled by the spokecolour control. The level of detail seen is controlled by the spokes control, and the visual impact of a given diagnostic is controlled by the spokeshade control. The setting of the overshade control has no effect when canonical wheels are being produced.