Lena test image

There are two kinds of people in the world. The first have seen the Lena (or Lenna) image before; most of them have done at least some work in image processing, or happen to have read the November 1972 issue of Playboy magazine. The second have probably never seen it. read more

Submitted on 30 August 2012

Fractal Dimension

The concept of a fractal dimension is based on the idea of measuring things with differently sized rulers, as already mentioned in the article on the Mandelbrot Mandelbrot set. Mathematically (but very loosely), the fractal dimension is defined as: if I cover an object with… read more

Submitted on 17 June 2012

Mandelbrot Set

Detail of the Mandelbrot set

The Mandelbrot set is named after Benoît Mandelbrot, a French American mathematician. The set is a part of the complex plane. It is created by iterating the complex quadratic polynomial \(f_c(z)=z^2+c\). For each point \(c\) of the complex plane… read more

Submitted on 17 May 2012


Detail of the Mandelbrot set When I was writing an article on the Mandelbrot set, I looked for software to generate illustrations. Needless to say that there is lots of stuff available for a colorful subject like that. But, lo and behold, I discovered that the venerable Fractint still exists, and is actually still maintained! The program…


Submitted on 1 May 2012

Where to Launch Your Rocket?

If you want to launch a rocket into space, as I’m sure practically all of you are at least contemplating, where should you do that? The main thing is of course to avoid populated areas, to limit the damage if the thing blows up. The launch pad itself should be located away from people, and there should be a large uninhabited region to the east of the launch site… read more


Submitted on 10 April 2012

Infinity and Beyond

If you think about a set with an infinite number of elements, you might conclude that there is not much to say about the number of elements anymore. Infinite is infinite, right? Well, it turns out that not every infinity has the same “value”, and that there’s actually quite a lot to say about it. Take the natural numbers… read more

Submitted on 26 March 2012

Euler’s Identity

Euler’s identity using Hama beads

Euler’s identity, \(e^{i\pi}+1=0\), must be the most beautiful formula in the whole of mathematics. The expression establishes an amazing relation between five important numbers… read more

Submitted on 11 March 2012

Pinhole QR CodePhoto Page

Pinhole QR Code

I’ve actually found a way to combine quality time with my seven year old daughter, pinhole photography, and QR codes. Together, we created a QR code from those Hama beads that you iron together. Taking the pinhole photo was easy. read more


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