Sharing my personal interests.

Investigations into mathematics -- group theory, integrals, continued fractions, matrices, geometry and more.

Also music and art: the acoustics of the violin family of instruments, music created by computer, plus some paintings, drawings and local history .

 
 

Welcome to John Coffey's web site of interesting finds.

This site is for maths students and amateurs who enjoy exploring maths, music, and acoustics. I am not a professional mathematician, musician nor artist, so there are no high-powered research papers here -- just the work of an enthusiast.

The latest additions include several paintings and drawings plus

1) A 34 minute film presentation about a demolished Victorian iron railway bridge -- a study in industrial archaeology. The video is on Youtube and accessed by this link.

2) A copy of a report on ultraonic non-destructive testing -- signals from rough facetted cracks. I wrote this while working in the electricity generating industry many years ago.

3) A review of the modelling of trees by computer, including fractal trees, L-systems, biology-based models of growth, and CGI applications such as SpeedTree, UE5 and Houdini.

4) A simple account of photogrammetry -- the process of determining 3D information from 2D photographs. It covers the principles of calculating object positions in a scene from overlapping photos. Also stitching images together into a parorama, and other aspects of computer vision..

5) Drawing in perspective: How simple objects appear when drawn accurately. This includes a section on how computer graphics software rotates an object, plus an account of non-linear perspective using the map projections. A supporting article describes spherical triangles,

Click the buttons above particular topics,

or here for an overview of contents and other topics

John Coffey, Cheshire, England, Easter 2026