Inspired by travelling down the motorway and the Dr Who programme guides I've been reading...
Time is a one way process. In the same way that we travel down a motorway, we live life in one direction. The speed of the journey depends on the driver - some people enjoy the speed and thrills of living life at 100mph, but they will reach their journey's end faster as well. Others are juggernauts, bulling their way through, intimidating the slower drivers who don't want to conform to the speed that the lorry is going. Slow drivers might seem to potter, but they get there in the end.
But what if, as on a motorway, we could see people coming the other way? Those who have already lived through what we are about to encounter? People who, unknowing of what they are doing, could give us a clue as to what lies ahead. We would have to be skilled at reading the signs - the lit headlamps and slowing windscreen wipers showing the storms ahead. Occasionally, one or two would be aware of us, and try to alert us, flashing their headlights to warn of the police speed checks.
And, once we became aware of the opposite flow, could we find a way to join them? To find the junctions and roundabouts to travel in the opposite direction? To rewind time and our journey to the beginning.