Spontaneous_symmetry_breaking_(explanatory_diagram)

Explanatory diagram showing how symmetry breaking works. At a high enough energy level, a ball settled in the center (lowest point), and the result has symmetry. At lower energy levels, the center becomes unstable, the ball rolls to a lower point - but in doing so, it settles on an (arbitrary) position and the result is that symmetry is broken - the resulting position is not symmetrical.