Puzzle on billpg industries™

A flag for Milton Keynes

Thu, 26 Sep 2019 19:19:18 +0000

I wrote this page before I found out that Milton Keynes City Council has held a flag design contest for children and already selected their new flag. This page is for the historic record.

Congratulations Milton Keynes on your new City status. All self respecting cities need a flag. London, Coventry, St Albans all have really good ones. You should have one too.

Having worked in Milton Keynes for over a decade, I was surprised to learn that Milton Keynes don’t have a flag. I was attending an event organised by a local group and they were using the “swan” flag of Buckinghamshire. This prompted me to set to work on a design.

Clever and totally pointless - my first publication

Fri, 24 Jun 2011 20:28:00 +0000

Way back in the early 90s, I subscribed to a magazine (think of it like a big website but printed on paper and sent through the post) called ‘PC Plus’. It included a section called “Wilf’s Programmers Workshop” where every month, Mr Wilf Hey would present a project (usually written in GW-Basic) and discuss the principles at work. It was here where I first managed to get something clever into print, except I didn’t do it quite right.

Vinegar - refined Vigenère - can you break my cipher?

Sat, 12 Feb 2011 16:32:00 +0000

I’m idly interested in cryptography, the art of scrambling a message so that it can be transmitted securely, and only someone with the magic key can understand the message.

When I was young, I designed a cryptographic algorithm. I thought I was so clever, but just because *I* couldn’t break it, that doesn’t make it secure.

In this article, I present my naive cryptographic algorithm. It’s very flawed, so please don’t use it for anything important. Can you find the flaw?

Computers are fast!

Sun, 29 Nov 2009 18:15:00 +0000

Killer Sudoku is a popular variant on the perennial Sudoku game found in British newspapers. The same rules about the numbers 1 to 9 appearing only once in row, column and 3x3 box still apply, but unlike Sudoku, the puzzle doesn’t come with any numbers filled in. Instead, cells are groups with dotted lines and the total of all those cells are written in. Here’s part of a puzzle. The two cells grouped by a 10 could be 1+9, 2+8, 3+7 or 4+6. (It can’t be 5+5 because that would mean two 5s in same box.) Not a lot to work on, but also look at the three cells grouped by a 23 in the same 3x3 box; The only possible fit is 6+8+9. This means the only possible fit for the 10 group is 3+7, as all the possibilities would clash with the 6,8 or 9 required to make the 23. I could go on. If you want to complete the puzzle, its the Guardian’s puzzle number 166. The point of this article isn’t to solve the puzzle, but something I observed along the way. Am I sure there’s no other way to split 23 into three parts, 1 to 9, without duplicates? I confess, mental arithmetic is not my forte. Part of the puzzle solving process for me is going through each dotted group and building a crib sheet on all the possible ways to make the total, so I can cross them off later. This isn’t a part of the puzzle I particularly enjoy, so I decided to automate it. (Is that cheating? I don’t think so in my circumstances, but that’s another topic of conversation.) So I sat down and designed an algorithm…