Rees snapped: "Status!"

The Mole rolled to a halt. It replied — as it always replied—"Massive sensor dysfunction." Its voice was thin and flat, and emanated from somewhere within its scuffed body.

Rees often imagined that if he knew what lay behind that brief report he would understand much of what baffled him about the world.

The Mole extended an arm from its nose. It reached to the panniers on its back and began lifting head-sized nodules down to a pile on the floor of the chamber. Rees watched it work for a few minutes. There were crude weld marks around the prow devices, the wheel axles and the points where the panniers were fixed; also, the skin of the Mole bore long, thin scars showing clearly where devices had been cut away, long ago. Rees half-closed his eyes so that he could see only the broad cylindrical shape of the Mole. What might have been fixed to those scars on the hull? With a flash of insight he imagined the jets that maintained the Belt in its orbit attached to the Mole. In his mind the components moved around, assembling and reassembling in various degrees of implausibility. Could the jets really once have been attached to the Mole? Had it once been some kind of flying machine, adapted for work down here?

But perhaps other devices had been fixed to those scars — devices long since discarded and now beyond his imagination — perhaps the "sensors" of which the Mole spoke.

He felt a surge of irrational gratitude to the Moles. In all his crushing universe they, enigmatic as they were, represented the only element of strangeness, of otherness; they were all his imagination had to work on. The first time he had begun to speculate that things might somewhere, sometime, be other than they were here had been a hundred shifts ago when a Mole had unexpectedly asked him whether he found the Nebula air any more difficult to breathe.