1. A machine-implemented method comprising: obtaining input image data from image input circuitry; the input image data defining an input image that shows a perimeter relationship representation, the perimeter relationship representation including a perimeters feature that satisfies a constraint on perimeters; the perimeters feature enclosing areas of the input image in a way that indicates a relationship among distinctions; using the input image data to obtain perimeters data indicating parts of the input image that satisfy the constraint on perimeters; the parts of the input image enclosing the areas of the input image enclosed by the perimeters feature; and using the perimeters data to obtain relationship data indicating the relationship among the distinctions.