  Two examples serve to illustrate the possibility of classical indeterminism. A very elegant recent example is provided by ‘Norton’s dome’ (Norton 2003; 2008). A point mass is at rest at the apex of a dome (of certain shape) at \(t^*\). One obvious solution to Newton’s equations of motion is that it continues to do so for all moments \(t \gt t^*\). But, Norton points out, there is another solution: that while at \(t = t^*\) the mass is at rest, at every moment \(t \gt t^*\), the mass is moving in some direction. But this means the mass spontaneously moves off in some arbitrary direction at an arbitrary  time.[21] Determinism is clearly violated: for some given time \(t^*\), there is a state at \(t'\) where the particle remains at the apex of the dome; and there are many incompatible states where at \(t'\) the particle is somewhere else on the surface of the dome. Nothing in the conditions at \(t^*\) fixes which of these many future states will be the one to eventuate. An easy way to understand the dome example is to consider its time reversal: a ball is given some initial velocity along the surface of the dome toward the apex. Too little, and it falls short; too great, and it overshoots. Just right, however, and the ball comes to rest precisely at the apex, and remains at rest. The time reversal of this system is the original dome example.