Ben North's blog.

Covering various topics, usually of a vaguely nerdy nature.
Contact: ben@redfrontdoor.org

29 January 2017

Exponential Mazezam level family

As a correction and follow-up to a previous post, I constructed a family of Mazezam levels whose solutions are exponential in the size of the level. Many thanks to Aaron Williams for pointing out my error to me. Full write-up and demo on GitHub.

09 November 2016

Joining and mapping government data sets

A while ago, the principal at the primary school my children attend remarked at how time-consuming it was for her to manually collate two different sources of information on schools, and cross-reference against a map of schools' locations. Her task, as I understand it, was to find nearby schools who might want to pool their […]

07 October 2016

Bletchley Park 'Rectangling' and LDPC codes

For now, this is my final post arising from the General Report on Tunny. I looked at the connection between: 'Rectangling', part of the cryptanalysis performed by the Bletchley Park codebreakers on the Lorenz cipher, and Belief Propagation decoding of LDPC error-correcting codes. See the write-up and code repo for details.

12 September 2016

Literate programming with git

As a follow-up to the previous post on git dendrify, I've been experimenting with using git to present the development of a piece of software in a more human-readable way. The hierarchical organisation described in the git dendrify README allows the history to be rendered into a structured and interactive document explaining the code's development. […]

15 June 2016

git-dendrify — a tool for transforming git histories

I've been working with git for a while now, and have been experimenting with it as a way to present the history of a piece of code in a way which makes it easier for a human reader to understand. One way I think git can help with this is by adding structure to the […]

14 May 2016

(Some of) Colossus on an FPGA

An implementation, on an FPGA, of the parts of the Colossus code-breaking computer needed to replicate the Chi-wheel-setting worked example of the previous post.

12 April 2016

Replicating Colossus's Chi-wheel setting

A worked example of one part of the cryptanalysis performed by the Colossus computer at Bletchley Park during World War II.

23 February 2016

Bike Game in Scratch

Just over a year ago, my son (then 6) wanted to create a computer game where you drive a bike round a world. I helped him with this, and we've worked intermittently but fairly often on it since then. There were quite a few details to get right, but he worked through them a bit […]

13 September 2015

Flying over a trampoline

Origin of idea A couple of months ago, Sally (5) was bouncing around on the trampoline at my in-laws' house, and said something very close to: 'Dad, you should take lots of pictures of me jumping in the air, and put them together into a video, then it will look like I'm flying'. I thought […]

05 August 2015

Mono Lake alkali flies in JavaScript

We recently went on a fantastic family camping trip to California, travelling round various National and State Parks. One of the places we saw was Mono Lake. There are lots of interesting aspects to Mono Lake, but this post concentrates on one of them: the vast numbers of alkali flies which live on the waterline. […]