You might be interested to know that Banks was once asked whether the Culture was a utopia or a distopia. He replied, "Yes."

Does it bother you at all that that is not at all what he said? I ask because it makes me sad to see a human being incapable of parsing a very simple piece of text. Many people are dispirited by the realpolitik practised by most parties with any actual power, by the lobbying power of industries and of special interest groups with views which appear grotesque or simply stupid, and by political corruption. Furthermore, many countries have voting systems which are conservative - the populace tend to vote for the incumbents, or oscillate between two power blocks which are not radically different from one another. To state that most parties appear not to represent ones beliefs is very different from saying that one has almost no beliefs. Democracy, as it is currently practised, is certainly not a pleasant sight for an idealist. I'd do something about it, but I don't think I have the stamina, money, cynicism and skills. At least I can understand a simple post though.

No, white noise is random, which wouldn't have the same properties as this. For a start, it would have the same key more than once.

Well spotted (by which I mean, mod parent up!). He could have used a larger primitive root of 89, like 30, and that wouldn't have occurred.

Interestingly, if you try to generate more than 88 notes by the method Rickard described, they start to repeat periodically.

It is, but not of the kind they were looking to avoid. There are Costas arrays without that pattern, but they're not known for sizes over 28 x 28. They're called 'sporadic' arrays, and they're actually the most common type for small sizes (there are infinitely many generated by field theory, but that's not a fair comparison as we can't find large sporadic arrays).

Please note that "note a musical guy" was not intended as a pun, but was in fact my brain on too little sleep.

No patterns?

I'm note a musical guy, but I understand the maths, so I'll try to answer this.

1. He never plays the same note twice. (A Costas array is a permutation) In a random piece, the same note can (and probably will) appear more than once.
2. If he plays middle A, then middle B (consecutive notes), he'll never play consecutive notes (e.g. C_0 and D_0) again. 3. If he plays middle A, then something else, then middle B, he'll never play consecutive notes spaced by another note again. 4. If he plays middle A, then two other notes, then middle B, he'll never play consecutive notes spaced by two other notes again. 5. etc. 6. The same applies to pairs of notes two notes apart (e.g. middle A and middle C), three notes apart, etc. 7. Finally, he uses a Golomb ruler for the spacing between notes. I'm note quite sure what he did there, but possibly each spacing is unique. Can someone else explain? At any rate, a Golomb ruler defines unique gaps such that you get every possible gap between some pair of marks on it. (Think of a 4 cm ruler with 0 cm, 1 cm, 2 cm and 4 cm marked on it. You don't need a mark at 3 cm because you can get that from the gap between the 1 cm mark and the 4 cam mark.)

Can't is note quite true, but won't is more like it. Consider 3.14159265358979323 - the first 18 digits of pie. Random digits? Maybe (randomness, as you note, needs to be defined). However, look at triplets: 141, 535, 979, 323. Played as music, people will hear repetitions like that. Or at least, that seems to be the theory; I have no ear for these things to test it. Maybe you can hear them?