What a lovely sense of color and motion! The geometry of shapes in this image really pulls me in! However, I have to agree with some of your commentors that the relationship to the challenge is somewhat weak and mostly argued in the title.
The image itself is exciting to look at...all the way to the little stars made by the lights. I feel the composition could be strengthed by a different point of view. The cropping of the top of the wheel is fine but I'd like to be viewing this from about 15 degrees to the left so the wheel would appear more round. The lamp in the lower right hand corner is also a liability, in my view. It demands attention because it is so well defined against the black space.
Overall, a great subject and a wonderful approach to it!
Keep shooting!
I didn't give much credit to those using a mere circular theme to represent pi. Too weak. If a diameter would have also been included then at least the maths would be better represented.