Sorry VisualLab for the late reply, as I have been a bit sick (with a viral infection). I still remember how you helped me out with regular polygons many moons ago (when I was learning Lazarus). Thanks for your nice words. I just love using mathematics to make programs that create different sorts of interesting patterns.
This program I thought created identically repeating fractal patterns. but after investigating a bit I see it does not create identical repeating patterns. Colouring identical bits with particular colours showed variations in the pattern.
I had thought of maybe combining all my curve programs to make one program that does all, but I am sort of heading towards learning how to make and save as SVG, using Bgrabmp (instead of just png). I can see how they can be used for textile handicrafts such as embroidery, weaving, crocheting. Saving as SVG would mean that we could enlarge or shrink the patterns and not lose quality. Even thought of making plugins for Lazpaint in a similar way to Paint.net and GIMP.
Been running out of hard disk space (because I keep creating samples of lots of patterns), so will need to perhaps get another laptop with a bigger hard disk. Also would be nice to perhaps see different OS versions (bought a 2nd hand Mac but need to set it up with Lazarus). Too many ideas and not enough time in the day.
Thanks to the Lazarus forum members for their nice help and advice.