Individuals with this form of synesthesia see all numerical sequences that they have come across in space, in number forms.

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These number forms appear involuntarily when the individual thinks of numbers. In this number form, each numerical value is represented in space, where the distances between values differs. For instance, on a number form, the distance between the number 12 and 13 may be significantly greater than that between 23 and 24.

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While each number forms varies with each individual, no map changes with time.

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It has been suggested that this form of Synesthesia is the result of cross-wiring in areas of the parietal lobe and angular gyrus that are involved in numerical and spatial recognition.