When used as an analogy for progress, what does the spiral suggest about revisiting old themes?

Answer

That progress is rarely linear, involving revisits from a slightly different, more evolved perspective.

The spiral serves as a structural analogy suggesting that progress is rarely linear; one revisits old themes or challenges, but does so from a slightly different, more evolved perspective.

When used as an analogy for progress, what does the spiral suggest about revisiting old themes?
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