Legendre polynomials can be given by several expressions, but perhaps the most compact way to represent them is by Rodrigues' formula as
$$P_n(x) = \frac{1}{2^n n!} \frac{d^n}{dx^n} (x^2 - 1)^n.$$
I was wondering if there exists a multidimensional variant of the Legendre polynomials, e.g. an analogous $P_n(x,y,z)$ for instance. Does anyone know anything about this? I can't seem to find anything about it.