I am a visual thinker.... so I have a mental picture of things.... and time is a spiral. {like pete1061 said} We go around, but we don't end up at exactly the same place, we are a little bit forward, and it is never ending, thus you have a spiral.... or, my picture is more like a tightly wound coil hanging from a wire... since we arbitrarily assign a "stop" point on Dec 31 and begin counting again... and that line intersects each and every year at the same place.... (clear as mud, right?) anyway, imagine someone threaded a clothesline through a coil-sring and strung it between the clothesline posts so the "bottom part of the year" hangs down, and the dividing line is at the top.... each year being a circle, summer at the bottom, the line between Dec and Jan at the top. That works out well for your solstices and whatnot also.... (LOL, imagine all the confused looks I'm getting right now.... )
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{the avatar is a Claude Monet}