`In fact,' said Ponder Stibbons, Head of Inadvisably Applied Magic, `theirs is really only a QBT, or Quite Big Thing. Actually, they've had so many problems with it, it's probably only a BT!'

The senior wizards nodded happily.

`And ours is certainly bigger, is it?' said the Senior Wrangler.

`Oh, yes,' said Stibbons. `Based on what I can determine from chatting to the people at Braseneck, ours will be capable of pushing boundaries twice as big up to three times as far.'

'I hope you haven't told them that,' said the Lecturer in Recent Runes. `We don't want them building a ... a ... an EBT!'

`A what, sir?' said Ponder politely, his tone saying, `I know about this sort of special thing and I'd rather you did not pretend that you do too.'

`Um ... an Even Bigger Thing?' said Runes, aware that he was edging into unknown territory.

`No, sir,' said Ponder, kindly. `The next one up would be a Great Big Thing, Sir. It's been postulated that if we could ever build a GBT, we would know the mind of the Creator.'

The wizards fell silent. For a moment, a fly buzzed against the high, stone-mullioned window, with its stained-glass image of Archchancellor Sloman Discovering the Special Theory of Slood, and then, after depositing a small flyspeck on Archchancellor Sloman's nose, exited with precision though a tiny hole in one pane which had been caused two centuries ago when a stone had been thrown up by a passing cart. Originally the hole had stayed there because no one could be bothered to have it fixed, but now it stayed there because it was traditional.

The fly had been born in Unseen University and because of the high, permanent magical field, was far more intelligent than the average fly. Strangely, the field never had this effect on wizards, perhaps because most of them were more intelligent than flies in any case.