Variation

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A variation is a group of headmates similar to a subsystem, yet different in the fact that members feel like separate yet similar members whose memories click together like a puzzle. Members of a variation will typically have been active during different time periods, most likely one right after another, and it is likely that these members once identified as one person before recognising their difference in identity.

A member of a variation is a variant. Variants may feel more or less connected to others, and may have more or less memory overlap with other variants.