self-normalised-axes-need-a-second-shape

Build a radar/fingerprint chart whose axes are normalised 0..1 from your own data — no external corpus, one guarded denominator per axis, and a second polygon (the previous period) because a lone shape on self-normalised axes says nothing. Use when a "usage personality" or "year in review" chart needs a reference it cannot get, when a thin period leaves one axis at a guarded zero beside four real readings, or when…