Gender, advanced mathematics
Gender is actually a spectrum in H⁴, but we, being humans used to E³ and being completely unable to imagine 4D hyperbolic space, have simplified it down to, at worst, a binary and, at best, a spectrum in R² with some options off the plane. Not even all of R² either. Just the positives.
Gender, advanced mathematics
I supposed technically, it should be a spectrum in E², as technically both H² and E² are diffeomorphic onto R²