$$f(x,y)=\frac{2}{x^2+(y-1)^2+1}-\frac{1}{x^2+(y+1)^2+1}$$ will do. Indeed, this function $f$ has a saddle point $(0,\approx-8.54)$, a point of a local minimum at $(0,\approx-1.14)$, and a point of a local maximum at $(0,\approx1.04)$. --- Below are the calculations, in Mathematica: [![enter image description here][1]][1] [![enter image description here][2]][2] [1]: https://i.sstatic.net/LAsPA.png [2]: https://i.sstatic.net/P8cgD.png