Python Minecraft CoderDojo -- Play Testers Sought

I've updated the sheets for the Manchester (UK) CoderDojo Python-Minecraft project.  I'm looking for play-testers.  If you are interested, take a look at this on the Minecraft Forum:

http://www.minecraftforum.net/topic/2427342-python-programming-sheets-for-coderdojo-play-testers-sought/

Jitsi VOIP Client DTMF Settings

It took me ages to find out how to modify the Jitsi DTMF settings today.  In case you have the same problem, here is a pictorial guide:

The Corn Laws

The Corn Laws where tariffs imposed on the import of corn to the UK from 1815 to 1846.  The intention of the tariffs were to protect the interests of corn producing landowners.  While landowners benefited from the protection of their markets, low-paid workers experienced poverty and famine from having to spend a large proportion of their income on bread.  The struggle to repeal the Corn Laws led to the collapse of the Conservative government and the resignation of Robert Peel as Prime Minister.  Following their repeal corn prices fell in the UK resulting in the reduction in the amount of land dedicated to cereal production and a similar reduction in the demand for agricultural labour.

Mainline vs. Trunk Development

In software source control (git, mercurial, etc.) you branch the code base in order to isolate different development efforts from one another. In a "mainline" source control model fixes are made on the branches and then merged into the mainline. In a "trunk" source control model fixes are made on the single trunk and then pulled into the branches as needed for a release.

Paul Hammant provides a nice picture of this in which he expresses his preference for the trunk model here: http://paulhammant.com/images/mainline_vs_trunk.png

The Pigeonhole Principle

The Pigeonhole Principle is a counting argument method of mathematical proof.  It says that if you have more items to distribute than pigeonholes to put them into then at least one of the pigeonholes must contain more than one item.  This simple principle becomes interesting when you extend it to countably infinite sets, e.g. the natural numbers.  See: http://en.wikipedia.org/wiki/Hilbert%27s_paradox_of_the_Grand_Hotel