Every few years I decide to have a go at using a CAD package for the creation of 3D diagrams…

### The Gini coefficient and income inequality in Australia

According to Australia’s national broadcasting network, the ABC, inequality is increasing. This claim has been refuted by several academics. Now…

### The world’s best map projection

As is well known, you can’t squash the surface of a sphere (or of a hemisphere) flat without either tearing…

### Let’s hear it for Logo (3)

Logo is of course known for its turtle graphics, and such is the appeal that there are now turtle graphics…

### The derivative of sin(x)

We know that we can use the limit definition     to compute the derivative of “from first principles”. And…

### Tuning and temperament (3): Just Intonation and Equal Temperament

We have seen in previous posts on this topic that: The perfect fifth corresponds to a frequency ration of 3/2…

### Tuning and Temperaments (2): Intervals and Pythagorean tuning

In the previous post we looked briefly at intervals, pitches and frequencies, and how to measure them.  We also showed…

### The size of the Solar System (and more)

I’ve been looking up at the sky at night recently, and thinking about the sizes of things.  Now it’s all…

### Neusis constructions (4): the Delian problem

The Delian problem is that of constructing ; since the polynomial equation is irreducible over the equation can’t be solved…

### Neusis constructions (3): the regular heptagon

The regular heptagon (seven sided polygon) is the smallest polygon which can't be constructed used Euclidean compass and straight-edge.  However,…