Geek Dinner at the Texas Embassy

Saturday night was time to get back in to the flow. Ian Smith suggested I come along to the Geek Dinner and I'm glad I did. As a new dad I have limited time for reading (and writing) blogs, and I spend very little time listening to podcasts, but the blog/podcast focus of the evening had a feel very reminiscent of the early days of the internet: lots of geek enthusiasm, no clear business models, and a world still small enough that a newcomer can get to know people.

I left after dinner and missed the talk by Roger Scoble, but Hugh Fraser and I snagged each other as fellow geek diners on the way in, and it was good for me to get the picture from someone who's actually in the blog/podcast business - and while I may have missed the speech I caught Hugh's interview which is naturally available as a here as a podcast.

Just to prove I was there, I'm third from the right here, with Ian on my right and Sarah Blow in the near left corner.

[added: 2005-12-15] A chance to pay my respects to two travellers that I met at the dinner - Nicole Simon, over from Germany just for the event, and Regular Jen who's made the big move to come over here from the US and get married to Neil Dixon (the kind of move I've never had the guts to make myself, but instead inflicted on my own wife).

Little Johnny and the friendly stranger

We were taking a bus back to Brixton when a man thanked Eva, me and little Johnny for moving the pram so he could wheel himself into the wheelchair space which we had been occupying. Nice, but he then complimented Johnny on "her" looks.

"Call little Johnny a girl again and he'll probably head butt you", I warned him, with some reason. Not only does the boy tend to go into woody-woodpecker mode when hungry, banging his head furiously against anything that looks vaguely like a human chest - male or female - but he has also started trying to throw himself head-first out of whichever arms are holding him.

We're beginning to wonder if the first words following his current kitten-wails will be not "dada" or "mama" but a lusty Scots cry of "Stitch that, Jimmy" as he administers the dreaded Glasgow Kiss to whichever doting adult has unsuspectingly come in range of his forehead.

How does a psychic website do THAT?

An amusing web site that correctly chooses a symbol matching the two-digit number you have chosen at random.

These things always raise two challenges - first: how does it work, second: if you can see how it works, can you explain it in such a way that others can too?

So don't read on if you'd rather work it out for yourself!

The instructions are

Take any two digit number, add together both digits and then subtract the total from your original number.

When you have the final number look it up on the chart and find the relevant symbol. [...]

First, the result of adding the two digits and subtracting them from the original is always a multiple of nine.

Why?

Well, try subtracting the left digit and the right digit in separate steps, eg

instead of
[1] 3 + 5 = 8,
[2] 35 - 8 = 27.

do
[1] 35 - 5 = 30,
[2] 30 - 3 = 27.

So the subtracting the right digit always leaves you with a round number, a multiple of 10, and subtracting the left-column digit subtracts 1 from each of those 10s, leaving you with a multiple of 9.

Now take a look at the table of symbols and note that each multiple of nine maps to the same symbol (a sun sign the first time I looked, a moon symbol the next).

Thanks to Andy Naughton for a great puzzle, and my apologies if you find this explanation far less amusing!