Lindsay Logan obituary

My father, Lindsay Logan, who has died aged 79, was emeritus professor of Dundee University and a distinguished educationist. He was head of the maths department at Northern College, Dundee, before it amalgamated with the university, where he became head of maths education. Through his passion for the teaching of mathematics, he made a significant…

Can social interactions affect spread of disease?

Most real-world systems, such as biological, social, and economic schemes evolve constantly. The dynamics of such systems are characterized by significantly enhanced activity levels over short periods of time (or “bursts”) followed by long periods of inactivity. This is true of social communities, in which the pattern of connections between individuals progresses over time, and…

Did you solve it? An Aboriginal family puzzle

Earlier today I set you the following puzzle: Aboriginal groups are divided into subgroups, called “skins.” Your skin is determined at birth, based on your parents’ skins, and it does not change in your lifetime. Your skin will determine certain social rules, such as who you are allowed to marry. The Warlpiri, who live northwest…

Can you solve it? An Aboriginal family puzzle

Hi guzzlers, Today I have a logic puzzle based on the complex kinship rules found in Australian Aboriginal society. Aboriginal groups are divided into subgroups, called “skins.” Your skin is determined at birth, based on your parents’ skins, and it does not change in your lifetime. Your skin will determine certain social rules, such as…

Did you solve it? Five shady puzzles

Earlier today I set you five puzzles from More Geometry Snacks. Here are the questions each followed by two methods of solution. Sometimes the simple action of drawing in a few extra lines reveals the solution clearly. 1. A point inside a square is connected to its four vertices. What fraction of the square is…

Why is this line so long?

One line spreads the risk of slowdowns out over the whole group. Credit: James R. Martin/Shutterstock.com Warning: After reading this article, you will never again stand in a line without thinking about how to make your wait time shorter. And as an expert in operations management, I’m here to spread the word that sometimes a…