Like the rest of us, most violent fundamentalists have families, and so they also have to reconcile the love and compassion that's engendered in them by the family structure, with the cruelty and pain that they inflict upon others. And the principal way in which they do this, is to convince themselves that whatever they do it, they do it in the name of love.

Perhaps the greatest exposition of this dilemma is to be found in the Sanskrit epic, the Mahabharata. In particular in the 18 chapters of the Bhagavad Gita, written about 400 BC in which Krishna, the god of love, advises the reluctant warrior, Arjuna, on the eve of battle. Krishna's advice boils down to this: Arjuna, get a hold of yourself; no-one likes the prospect of imminent violent death, but a man's got to do what a man's got to do, especially when his kith and kin are threatened. And if he does it with a pure heart and a clear mind, everything will be just fine.

There's so much truth, so much joy and love in the Gita, that it seems criminal to pass over it so lightly here. It portrays the struggle between conviction and doubt, and between deliberation and action. At the moment of truth, you find that what you want to do and what you must do are not always one and the same thing, and in these moments are born heroes.

Stirring stuff, but as the English novelist, Susan Ertz put it, millions long for immortality who do not know what to do on a rainy Sunday afternoon.

Farritor's team hopes to get the unit price down to $200 (£110).

"At that price I believe the savings will mean it will still be affordable if one dies in the line of duty," said the engineer.

It is envisaged the road markers would be delivered to a location by a specially equipped truck.

A camera on the vehicle would image the road and send a picture to a worker's laptop. The worker would then indicate on the screen where they wanted the bollards to be deployed.

Software developed by the Nebraska team would then obtain the precise coordinates and feed these to the "shepherd" unit so it could lead its herd of red robots into position.