Hello, I remember from school that a square is defined by 4 first degree equations (ax + b ) with limits for X and Y ( inequalities).

However, a square is a closed line , as much as a circle. So is there any way to define it with one equation, as we do with a circle x^2 + y ^2 = 1 ?

Suppose the square is within a circle . So have the equation for the circle. I saw in the wikipedia there's a form called astroid x^(2/3) + y^(2/3) = 1. It ressembles already to a square ... So maybe joining both a circle and an astroid can lead to an answer ? It seems to me the usual algebraic definition for a square in a graph , with its inequalties is much less esthetic than one euqation.

https://en.wikipedia.org/wiki/Astroid

thank you

ilan etam