I upgraded my home Linux box to Debian 3.1 last night.

I remember upgrading to Debian some time around 1998, because of its surprising tendency to Just Work and to get things right which other distributions got wrong. Either I had a very unlucky and unusual experience last night, or somewhere between then and now it has lost its way. Badly.

The good news is that British Gas have managed to send me an electricity bill with the readings the right way round. And they did it within the ten working days they promised, too.

The bad news is that it still says I owe them £500, and (although I will check it carefully tomorrow) might perfectly well be right owing to two years' worth of meter reading underestimation. Still, it's not nearly as bad as the £1500 they made up to begin with. And their gas side owes me a vaguely comparable sum of money due to overestimation, so it all works out plausibly in the end…

Over the past three days I've been putting together a Minesweeper clone to go in my puzzle collection. As of now, it seems to be pretty much playable.

To write yet another Minesweeper clone in this day and age, you have to have some pretty impressive added value to avoid accusations of gratuitous reinvention of the wheel. My added value is that I use sophisticated grid construction to ensure that all puzzles generated can be solved without needing to guess. No more getting to the last four squares and finding you have no choice but to take a 50-50 gamble.

What I hadn't realised before actually writing this and playing with it is that it permits much denser grids. The Windows ‘Expert’ level has a mine density of a bit over 1 in 5, and it's already sailing close to the limit: I've generally found it quite rare to get to the end of an Expert grid without having to take a nasty risk. If you tried getting any denser with random generation, you'd just have a vanishingly small chance of actually completing anything. But with my intelligent generation, you can raise the mine density by nearly another factor of two: I've successfully played games on the same size of grid (30x16) with 190 mines. At that density there are barely any blank areas to work round the edges of; almost the whole grid is taken up by fiddly work involving squares marked between 3 and 6, and there's no let-up. And it's fun.

Now I just need to find a way to go to sleep tonight without dreaming about Minesweeper…

I have clearly become more mature and self-controlled since I was eighteen.

I can tell this because that was the previous time I had half an hour of sleep in a night due to insomnia. At the time it put me in such a bad mood that when I got up I had a temper tantrum, hurled a hairbrush I'd had since childhood across the bedroom, broke it, and spent several years trying to find a replacement that worked nearly as well.

Last night I had half an hour of sleep again, and all it left me with was a steely determination not to take any nonsense from anyone today. Which probably worked out well, since British Gas sent me another fictitious bill yesterday so I had to ring them up this morning to argue some more. After browbeating them with a pageful of facts that I'd carefully collected since our last frank exchange of views, they agreed (again) that they were wrong and I was right, and promised (again) to send me a revised bill which made sense. I don't feel 100% confident that they'll actually do so, given that they didn't the last time, but it's something to hope for at least.

So here I am at work regardless, brain mostly made of cheese (and not even nice cheese – perhaps that plastic cheese-alike you melt on top of beefburgers), rather hoping that I can find something to do today which won't require me to think very hard. Perhaps I'll empty my inbox, or something like that. I fear I might not manage to get to the Calling tonight either, which is a shame, but if I'm going to fall asleep then better to do it at home…

I spent the weekend working on my puzzle games (again). This time I arranged for Net to guarantee a unique solution, and also wrote code to print out Net puzzles so you can solve them on paper. The latter was a crazy idea I had on Saturday, but actually seemed quite playable once I'd got used to the idea and tweaked the graphic design a bit. If anyone's interested, I've put up a sample sheet (one wrapping and one not) at http://www.tartarus.org/~simon/20050523-netsample.pdf.

I was staggered by the low quality of the competition I'm up against in the desktop-puzzle-games niche. I discovered this week that there are several more implementations of the Net concept than mine and the one I pinched the idea from; quite a lot of the others go by the name of ‘NetWalk’ or trivial variations on same, and I count two or three Linux versions and a Windows one. The Windows one is particularly impressive: as far as I could tell from the website, it has no ability to generate its puzzles automatically, relying instead on a large stored database of them. Once you use up the database, you're stuffed, unless you design your own by hand – at which point you're apparently encouraged to submit them back to the authors for inclusion in the next version. And for this privilege they charge you $10 for a copy (and I wouldn't be surprised if they also charge for upgrades and extra puzzle designs), while all the free versions generate an endless supply of random puzzles. That's the Windows world for you.

Also it occurred to me recently that writing solvers and generators for puzzle games is a field in which I feel extremely at home, for some reason. I think it hits a sweet spot between several of my skills. I'm first and foremost a programmer, but also I have maths training, which means I'm well placed to be able to prove properties of the puzzles I'm working with and thus simplify my code. Also, writing solvers is about half algorithms – a particular interest of mine – and the other half is figuring out how to write an automated solver for the puzzle in question in the first place, which seems to me to be a self-awareness thing: solve one by hand and pay attention to the things you're thinking as you do it. And self-awareness itself is something that's always interested me. As a result, when I'm been doing this sort of stuff, I get extremely absorbed and enthused by it and it's a terrible let-down to come back to (say) work, at which I usually get to use at most one or two of my core skills at any one time.

Oh well. I'd better get back to work anyway…

I left work at about 16:15 today, due to a crippling network outage which the sysadmins couldn't even provide an estimated fix time for. I decided that meant it was futile to hang about and hope it got fixed, so I came home. Hopefully it'll be sorted out by tomorrow.

(Of course I don't doubt it will actually turn out to have been sorted out five minutes after I left; that'd be just Murphy's style.)

Anyway, I put the time to good use. I came home and finished work on a ludicrously clever idea I'd had yesterday, to ensure that puzzles generated by my ‘Rectangles’ program have unique solutions. To my surprise and delight, it worked, and worked nearly first time, in spite of being a pretty outlandish blue-sky sort of idea.

(If that ‘ludicrously clever’ sounds rather self-congratulatory compared to my usual tone of ‘people might conceivably be interested in…’, then this is my diary so tough. It is pretty rare in computing – in fact, it's pretty rare at all – that I do something so impressive that it makes me want to bounce around the room shouting ‘WOOHOO’ and ‘HOW COOL IS THAT?’ and ‘DO I ****ING RULE OR WHAT?’, but this is such a thing. I am excessively pleased with myself for what I've just accomplished.)

In other news, twenty-four hours of watching my electricity meter has re-convinced me that I am right and British Gas is wrong. The reading marked ‘normal’, which I claimed was daytime and they claimed was night, moves only during the day. The reading marked ‘low’, which I claimed was night-time and they claimed was day, moves only during the night. Now all I need to do is convince them of this…

This morning I finally got round to ringing up British Gas and chasing up the revised electricity bill they said they'd send within ten days of 13th April, after agreeing with me that my day and night meter readings had been switched around and therefore I didn't owe them £1500 as they had previously claimed.

It turns out that their specialist team has reversed its verdict, and just didn't bother actually telling me or anything. They have reverted to the opinion that the two meter readings are the right way round. I told them my meter had the words ‘low’ and ‘normal’ written on it, and they told me those are simply misleading and do not refer to the low night-time rate and the normal day-time rate as one might expect. They insist that the night rate is the one marked ‘normal’, which means that the expensive day rate is the one which has been rocketing skywards at high speed.

If this is accurate – and while on the one hand I find it easy to believe British Gas is talking twaddle, on the other I would also find it easy to believe that someone had connected up my meter back to front – then I may actually owe them £1500 after all. If this turns out to be the case, then I suspect it might be because my night storage heaters have also got the wrong idea about which half of a 24-hour period is which, and are helpfully doing all their heating in the daytime rather than at night. Annoyingly, the heaters don't have a clock or any kind of timing control on them, and neither do they have obvious lights to indicate when they're on, so it's rather hard to check this. I can only assume that they get some magic information transmitted down the mains line itself to tell them when the low rate begins and ends – in which case, perhaps a side effect of my meter swapping the rates round might be that it also misinforms the heaters? I know very little about this kind of technology, so I'm not sure what's a plausible explanation and what's not. (And it doesn't help that the heaters are currently off; if British Gas had phoned me back promptly then I could have done some tests in April, when it was still cold enough that I had the heating on anyway.)

It's all terribly confusing and not a little annoying. In the immediate short term I'm going to take meter readings twice a day to see which reading really moves during the day and which moves at night; after that I suppose it's going to end up being a complicated N-way faff between me, British Gas, the landlord, whoever installed the meter and so on. In the absolute worst case I do actually have £1500 I could blow on a backlogged electricity bill, but I'd really rather not if it can possibly be proved to be somebody else's responsibility.

Bah and grr. Perhaps I shouldn't have done this early in the morning; there's nothing like a blazing row before 9am to put a downer on your entire day :-/

I said in my last entry that I'd been inspired to reflection as a result of adding two new games to my puzzle collection, and then I proceeded to comment on something that had been brought to my attention by the first of those games. Here's something that was brought to my attention by the second.

Since I added two new games to my puzzle collection recently, I've had a renewed interest in playing puzzle games. As has happened before, this has led me to notice things about the way I play them and start having deep thoughts about how I – and how people in general – think.

Yesterday is the first time in my life that I've voted for a Parliamentary candidate who then actually won. That's a good feeling. It means I was a part of the boot that kicked Anne Campbell out of Cambridge, which feels good, and it means the person representing me is the one I'd actually have chosen out of the options, which is good as well. Also, I feel much more that my vote has been heard: it's one thing to make your lone gesture of defiance against the government and show up as a change in the last digit of the detailed vote count, but it's quite another when another few thousand people stand up and roar their defiance with you loudly enough to be heard in Westminster and seen as a yellow flare on the national election map.

On the other hand, it feels kind of strange that my MP is now not part of the government party. Before today, Cambridge had Anne Campbell, who was; and when I lived in Berkshire with my parents and the Tories were in power I remember their (our) MP being John Redwood. They wrote to him on at least one occasion and got some impressive results from doing so; I admittedly wrote to Anne Campbell and didn't (which is one of the reasons I'm so satisfied to have helped boot her out), but at least I felt that when I had a beef with government policy I could conveniently communicate it to a member of the government. So suddenly I feel a bit disconnected from the people in power; it seems to me that if I write to my MP to complain about some barking mad government initiative or other, he's more than likely to write back and say ‘well, duh’ or ‘*sigh*, yes, isn't it awful’ or some such. Which would be nice if I were after validation of my opinion and someone to commiserate with, but less helpful if I want something done about it.

Still, on balance things seem basically positive from here.

Today I have become older. Ho-diddly-hum.

It seems to have become a tradition in my group at ARM that on one's birthday, as well as buying doughnuts for the group, one also poses a puzzle of some sort whose solution is one's age. This seems like a fun enough tradition to propagate, so I'm going to do it here too.

At work last week I told hsenag that there was a really obvious puzzle for this age which I'd have to avoid using, and he correctly guessed my age just from that. If you can do the same, you can give yourself a particularly smug pat on the back.

For everyone else, here's a nonogram puzzle I prepared in advance. You can print it out and solve it on paper if you like: http://www.tartarus.org/~simon/20050503-birthday-puzzle/nonogram.pdf or http://www.tartarus.org/~simon/20050503-birthday-puzzle/nonogram.png.

Alternatively, anyone who has the ‘Pattern’ program from my puzzle collection should be able to just type in ( some numbers )

I got randomly bellowed at this evening. I was walking up Milton Road towards my mum's house, when a van or minibus or some vehicle of that general type drove past. Some lads leaned out of the window and jeered incomprehensibly at me, then laughed as they drove off into the distance.

To some extent I get annoyed by that sort of behaviour simply because they tend to be large and intimidating louts with an air about them of ‘I can be deliberately obnoxious at you because I know you can't do anything about it’. But it annoys me an enormous amount more when I haven't the faintest idea what it was about. If they'd been laughing at my hat, for example, that'd have been at least understandable – but I wasn't wearing it. The tiger design on my T-shirt might have been a believable object of ridicule, except that they started bellowing before they saw my front, so that wasn't it either. My flies were done up (and see previous comment about them not having seen my front yet). What was it about me that obviously said I was someone they should laugh at? It bothered me all evening.

Fortunately, I think I've worked it out now. There was a match at the football ground near my home this afternoon; my suspicion is that the winning team probably wasn't the home one, that the louts were away supporters, and that they were jeering at anyone who looked like a Cambridge resident in a ‘we kicked your butts just now’ sort of way. If that's correct, then all I did to arouse their scorn was to be on foot in Cambridge at the wrong time. Phew.

In other news, I've spent today writing another game for my puzzle collection. (Yes, another one. It just seemed like a good idea.) Any devotees of Rubik-style puzzles might be interested to have a go at Twiddle.

I've just returned to work after a two-week break. This means that most of today will be spent clearing up the rather large email backlog that has accumulated in my absence. It's annoying that this happens: my job is by no means always boring, but the first day or two after coming back from a holiday is always boring, which means that the end of the holiday is always a bad moment. If only it weren't for the backlog, the end of a break would at least sometimes not be so bad.

My vague plan for the holiday was to spend the first week doing as little as possible, after which I expected to get restless and start doing something useful and programmingy. This didn't exactly work, because the first week was entirely taken up by annoying domestic chores and errands (MOT season, faffing with prescriptions, being repeatedly on hold to British Gas, that sort of thing), and after I'd capped it by spending Saturday driving down to Reading and back to visit an old friend, I found I was still not remotely rested and needed another week of doing nothing at all to recover. On the second Saturday I did actually rediscover my enthusiasm for programming, but by then it was a bit late to do anything major with it. Still, I did my best anyway: my puzzle collection now contains an implementation of the game most commonly known as ‘Su Doku’, although it's somewhat unfinished.

Anyway; back to the inbox. Wish me patience.

It occurred to me yesterday that the lembas eaten by Tolkien's Elves must have an extremely high energy density and thus I'd expect it to be explosive, or at the very least dangerously flammable to be hurling around near your campfire.

So it just occurred to me to try to actually estimate the energy density of such a fictitious food and compare it with that of some known explosives – and I discovered after some googling that in fact TNT has an energy density about one quarter that of normal carbohydrate-rich food. Fascinating. So high energy density is not merely insufficient to make something explosive, but in fact it isn't even necessary. I'm surprised; my intuition said otherwise.

In other news, lots of people have commentated on the recent papal election and have said many insightful, witty and/or heartfelt things about it; but I'm faintly disappointed that I've seen not one person entitle their post ‘Episode IV: A New Pope’. There. I have nothing else particularly intelligent to say on the subject, but I didn't want that one to slip by completely unsaid.

There are long-term roadworks on the M25, starting just south of the M4 junction. This means that if you're driving to Reading from Cambridge, as I was this morning, you get stuck in the tailbacks from those roadworks just as you thought you'd survived the worst the M25 had to offer.

After crawling along in this jam for a little way, I saw a sign warning me about it (gee thanks). The sign said ‘Delays possible until Dec 2005’. Whoever chose that wording, I thought, was having far too much fun; meanwhile, better phone my destination and let them know I might be a few months late.

On the way back there was a jam on the M4, in which I crawled along for three miles or so at an average speed of perhaps 15-20mph, and eventually discovered that the entire cause of the congestion was an accident on the other carriageway, at which everybody on my side was slowing down to rubberneck. I imagine this will be old news to many readers, but I found it utterly gobsmacking that a slight glance to one side and perhaps a slacking-off on the accelerator, on the part of the drivers at the front of the queue, can slow down traffic by a factor of three two miles further back. Unless the drivers at the front really are slowing right down to 20mph to get a good look, which I'd find even harder to believe. I want to see a detailed replay of the incident (or one like it) as seen from a passing helicopter. Anybody got one?

Well, as it turns out, British Gas's specialist cock-up untangling team suck royally at returning phone calls, and I still haven't spoken to them directly at any point. However, they do seem to be good at their primary job: they just passed on some results through a normal peon and the upshot is that they have independently come to the same conclusion as I have about how my electricity bills got so weird. That's a relief; I expected the hard bit to be convincing them that I didn't owe them 1500 quid.

They tell me it's now all in hand and I can expect a more sensible bill within ten days. I confess I'm not holding my breath on the ten days bit, but it sounds basically hopeful apart from that.

Yesterday was a rather frustrating day on several counts.

For a start, on Sunday I had set up a particularly hard custom one-player Starcraft game against several computers, and won it on the first time of trying, so yesterday I tried to do it again quite a lot of times and was completely wiped out repeatedly. In the end it turned out that the computer had made a rare and vital mistake the first time which it never made again. I would have been perfectly happy to get wiped out every time I tried this; I'd have concluded that I'd bitten off more than I could chew and tried something easier. But to succeed with relative ease the first time and then get massacred repeatedly is particularly annoying! It's got that sort of ‘first time's free’ nature about it that sucks you in and gets you involved against your will.

Also yesterday I attempted to go to my local post office to do some administrative faff involving my food prescriptions, and was rather startled to discover the post office wasn't there any more and had turned into an ordinary newsagent when I wasn't looking.

When I got home from that abortive outing, I was even more startled to receive an electricity bill for nearly one and a half thousand pounds! On closer inspection it turns out that they arrived at this figure by switching round the day and night rates in the meter reading I provided recently; on even closer inspection it looks as if they have in fact been doing this ever since I moved in, and I didn't notice at first because the two readings started out roughly similar, and then continued not to notice because they've been estimating my bill (badly) and this is the first real reading they've had since 2003. So I rang up to complain and the guy on the phone said ‘oh dear, this is one for the specialist team I'm afraid’; so some time this morning I'm expecting a complicated phone call from a crack squad of full-time British Gas cock-up untanglers (what a job). Wish me luck. And probably them too.

Life continues to be relaxing. In particular, it rather carefully helped me relax for the last day or so by means of my broadband connection going down! It's just come back and NTL haven't rung me back as promised, which might mean I have to proactively phone them up and let them know that sending an engineer to get me out of bed tomorrow won't be necessary after all.

Actually sitting on the sofa physically all day would get tedious even in relaxation mode, so I'm pottering about the house doing tidying and organisational stuff. In particular, I've just catalogued my book collection, with the vague aim of using the catalogue as a who's-borrowed-what notepad among other things. In the process I discovered another practical use for a digicam: take snaps of each bookcase in the lounge, then go through to the study and type the catalogue up while referring to the pictures. Much better than running back and forth between rooms repeatedly with as many book titles as will fit in my head at once.

I fear, however, that even this is displacement activity to avoid the really daunting stuff, such as clearing up the study and cleaning out my ever-present rucksack of random useful stuff. Oh well. At least there's no pressure on me to do any of it.

I began my two-week break by going to bed and having what I can only describe as a very relaxing dream. In this dream, reincarnation worked, and worked properly with full memory of the previous life; so when I felt myself getting old, I transferred all my life savings into an anonymous web-based bank account and made very sure I could remember the password. Next thing I knew I was a five-year-old in another body with all my previous memories including that password, and lo, I was rich. Well, for a five-year-old, anyway.

There were two things that were particularly relaxing about this dream. One was the reasonably obvious one: that my second incarnation, and all subsequent ones, would never have the slightest fear of death, because they knew nothing permanent or bad was involved.

The other was that my biggest worry after being reincarnated was what I would say about it in my online diaries (whose passwords, of course, I could also still remember). It would, after all, involve recanting my lifelong lack of belief in weird supernatural stuff. (Specifically, my particularly strong disbelief in provable supernatural stuff; unprovable supernatural stuff like non-interventionist gods I have a marginally more open mind about, although I still think ‘probably not’ and ‘who cares anyway’.) The fact that merely posting to an online diary which was known to be owned by someone who was believed dead might make more waves than the things I chose to say didn't occur to me until I woke up :-)

Today my known commitments are to have lunch in a pub, and to sit on my sofa for three hours showing B5 to people. This seems likely to enhance my already considerable feeling of relaxation. Mmmmmm.