Given a set of points $S$ on the Euclidean plane, Onion Peeling determines the nested set $H$ of convex hulls on $S$. Define an analytical formula on $S$ which produces a point, not necessarily in $S$, that falls inside the innermost convex hull in $H$. The formula must not use $H$.
Post Closed as "general reference" by Denis Serre, Wadim Zudilin, Harald Hanche-Olsen, Andrés E. Caicedo, Qiaochu Yuan