The title of this weblog has two meanings. The first mathematical and the second is intellectual. Mathematically speaking, an iteration is the act of replacing a value by some function applied to that value. For example, the iteration of z \mapsto z^2 + c is the way that you compute the Mandelbrot set. You start with a complex number c and you iterate z \mapsto z^2 + c starting at 0 until z becomes large or you get tired of iterating. In the latter case you say that c is part of the Mandelbrot set, and you plot c = x + iy in the plane in black, as in the picture on the left.Mandelbrot set

CircleLimit3

A reflection is a reflection in the geometric sense, of reflection across some line of symmetry. Usually we are interested in a group of reflections and in pictures that are invariant under a group of reflections, such as the Circle Limit drawings of Escher, like the one shown on the right.

I also want to use the two words metaphorically. An iteration is one of many repeated attempts; a reflection is way of stepping back and looking at something from a new perspective. Just as the title has two meanings, the blog has two motivations. One is to explain some mathematics to both a general and a mathematical audience, and the other is to iterate and reflect on a large variety of subjects, especially ones in science, politics and religion. It is probably in the latter two subjects that I will not only inform and inspire, but provoke and offend.