Amazing tan lines.

Go on, I'm here to ask dense questions and learn dense answers.

I can see that the central graph is x^3, but what equation repeats it twice along the X axis, and am I missing a pun?

edit: ah is this a tan(x) joke? I'm getting there slowly!

Me, seeing the raised hair on the arm: "Oh, this must be about calculating the odds of being struck by lightning."

Reading the comments about tan lines: "Oh..."

that sun function is a bastard