It's fun that it's not just an approximation, it's a perfect Batman logo. If you put in on an issue of Batman, nobody would remark on it.
On Quora somebody asked who wrote it, and this answer came:
I wrote it many, many years ago. I was teaching at a few art schools throughout the greater Sacramento area, and I used it to engage my students in the topic of graphing. One of my coolest students (Mr. Wilkinson aka i_luv_ur_mom) posted it to Reddit back in 2011 and it went viral. These days, I'm a full time professor over at American River College, doing every thing I can to make math as enjoyable as possible.