Ben North's blog.

Covering various topics, usually of a vaguely nerdy nature.

15 January 2013

Meg's book: Laura's Troubles

For Christmas, my daughter Meg gave me a hardback book which she had made herself (with help from Bear), using one of the many on-line design-your-own-book outfits, Pixum. Pixum provides a Linux version of their book-design software, which is notable and encouraging. But I could see no obvious way of exporting to PDF, and wanted […]

17 December 2012

Braille in National Aquatic Centre lifts

I was wondering about the Braille signs in the lifts at Dublin's National Aquatic Centre, and it turns out they are in German (courtesy of the Wikipedia entries on German braille and Braille patterns in Unicode): Open doors ⠞⠳⠗⠀⠡⠋ Tür auf Close doors ⠞⠳⠗⠀⠵⠥ Tür zu Alarm ⠝⠕⠞⠗⠥⠋ Notruf Curious. See also this xkcd (thanks […]

17 December 2012

Raspberry Pi, Squeezebox, phone line

Motivation Long ago, I built a circuit which enabled a PC to monitor the phone line, and control the music system in our old house. Whenever somebody rang, it would pause the music, and announce the caller using voice synthesis. It was cool. Details are on a pre-blog page. Alas, when we moved house, the […]

11 December 2012

UK government consultation on Open Standards

Back in June, I submitted a response (also as pp.35--39 of a PDF on the Cabinet Office's site) to the UK's consultation on open standards in government. Today I received an email notifying me of the conclusions to this process. I have read through the UK government's 'Principles' document, and the following snippets are quite […]

05 November 2012

An unusual primality test

A few years ago, I came across The Computist Quiz, and one question in particular led to some interesting mathematics: Amphibious Discursion A predicate on positive integers: boolean isToad(int n) { return ( (n == 2) || (n == frog(4, floor((n - 1) / 2), 1, 0) - 1)); } is defined with the aid […]

02 October 2012

MazezaM is NP complete

Update 20170129: My claim that Mazezam is NP-complete is not shown by this argument. The argument does show that Mazezam is NP-hard, but it is not clear that Mazezam is itself in NP. See a follow-up post for more details. Many thanks to Aaron Williams for contacting me to point out my error. The post […]

01 October 2012


Fickle is a one-button Vic20 game written by my friend Malcolm Tyrrell. In it, you steer a character called Fickle through a maze, trying to reach a heart. I wrote AutoFickle, an automatic player for this game, which solves all fifteen levels straight through.

06 September 2012

Time-lapse: Tomato plant perking up

A time-lapse of a slightly wilted tomato plant perking back up after being watered.

01 July 2012

Another stop-motion: Witch stirring potion

Did this with Meg last Christmas day, but only getting round now to putting the loops in and uploading. The AGC in the webcam was playing up a bit, so I tried to fix the exposures but some flashing and colour oddness remains.

19 June 2012

Ireland's copyright consultation

Background Ireland's Department of Jobs, Enterprise and Innovation are in the process of conducting a review of how copyright operates in Ireland. They published a consultation document and invited submissions. The Irish Free Software Organisation made a submission, which I drafted. There were also several points about the paper which I thought were interesting, but […]