Gradient flow on Himmelblau
Himmelblau’s function f(x,y)=(x^2+y-11)^2+(x+y^2-7)^2 has four equal global minima. The gradient flow \dot x=-\nabla f(x) sends each starting point to one of them; coloring trajectories by their limit reveals the four basins of attraction. On a non-convex landscape the initial point alone decides the outcome.