Review of my T-shirt design [closed]

I would try and optimize the sum at the bottom a bit. Definitely we need parentheses around the $-1$, but just throwing them in will cause a bit of a mess:

$$\pi^2/12 = \sum_{n=1}^\infty ((-1)^{n+1}(1/n^2))$$

Plus, math that’s not typeset well already gives me a less-than-stellar vibe; I’m not a huge fan of the font there.

Instead, you could rewrite the sum a bit, if you have the space for it. The version below takes up only slightly more vertical space than the Sigma, if vertical space is a concern. It’s a bit less cluttered, and LaTeX’s job (technically Mathjax here) is to make sure the typesetting is as good as possible.

$$\displaystyle \frac{\pi^2}{12} = \sum_{n=1}^\infty \dfrac{(-1)^{n+1}}{n^2}$$