"the helix of development" is just my clumsy English, I don't know the exact term. hopefully, somebody will help us.

if you look at history you can see that all civilisations go through similar stages of development: they raise, stay in zenith of their power for a while and fall. after their fall a new civilisation arises. but the succession of circles is non-linear. Roman Empire was more developed than Babylonian, for example. so it is not " circles"; it is circles in 3D, circles on ascending levels, therefore "a helix"