In this tool, the columns on the sheet and the first 256 rows are shrunk to 1 pixel by 1 pixel size. Each cell is then coloured to create an image of the fractal.

The fractal is generated by a slight modification of the pseudocode given on this Wikipedia page.

The code is implemented by the following (fairly straightforward) macro in Module 1. The macro first takes in the user inputs and works out the co-ordinates of the points required. Each point is checked if it is a part of the Mandelbrot set and coloured according to the number of iterations.

The macro can be modified to change the colouring algorithm or to generate other fractal images.