A blog of Python-related topics and code.

The previous blog post described the normal modes of a chain swinging under its own weight. Here we describe the motion of a chain after an arbitrary displacement as a linear combination of such normal modes.

The description of the oscillations of a hanging chain was a problem in mechanics solved by Daniel Bernoulli in the 18th century and which led to the discovery of the class of functions known as Bessel functions.

A recent tweet by Fermat's Library noted that the Fundamental theorem of arithmetic provides a novel (if inefficient) way of determining whether two words are anagrams of one another.

Cellular automata (CA) can be used to generate mazes, as described on the LifeWiki. A commonly used algorithm operates like John Conway's Game of Life in that a cell is born if it has exactly 3 neighbours but the survival rule is more liberal: a cell survives if it has 1–5 neighbours (rulestring B3/S12345).

In astronomy, a *fireball* is a meteor bright enough to be seen over a wide area (either apparent magnitude greater than -4 or greater than -3 at zenith, depending on the definition used). The terms bolide and, for exceptionally bright meteors, superbolide are also used. A famous recent example is the Chelyabinsk meteor.