Near to where I live here in Ireland is the Newgrange Passage Tomb, which is a world heritage site. It was built around 3200BC and it is mind boggling how such a massive construction was built to such a high standard in those days. I have been inside it and the corbelled roof is still bone dry after all these years - no leaks! Anyway you can read all about it, if you wish, by clicking on the link above, but the reason I mention it is the Neolithic art which both surrounds it and can be found inside it.
I hadn't come across Rick's Sez tangle pattern before, and as soon as I saw it I immediately thought of the famous tri-spirals found on the Newgrange Entrance Stone (here second photo down) and inside here (11th picture down). That entrance stone is massive, it is almost taller than me. Looking at the indoor photos I could see other tangle patterns, did you spot Static? Also was that the beginnings of Magda's Graancirkel half way down? Did you notice any others?
Before I started my tile for the challenge I decided to draw a bijou tri-spiral tile in honour of the pre-historic people who made the art-work. I then proceeded to fill in this week's string and then turned it on it's side because then it looked roughly the shape of the entrance stone.