I've been porting over our art program to a web version so you will all be able to play with it soon. It makes pictures in BBC micro Mode 2. It was a bit of an effort. Most of the tools are done. Now I can paint on my phone or Ipad. That was the reason I wanted to do it. It's all in javascript.
@PyDPainter Thanks. It's done in BBC Basic on an 8 bit BBC Micro and the Graphics Extension Rom. The Rom was special as it made up for the lacklustre graphic routines in the BBC Micro. It allowed dithering so you could get lots more out of the palette by mixing the standard 8 colours. If you look up pixelblip on twitter you will see a lot of art I do with it ( or blippypixel on instagram)
After 10 years - and the reason I started my art and my art program to solve this - today I finally set out to do what I wanted - in code. A poster fell off the wall one day that I bought. As I sat on the bed looking at the wall I thought 'Could the Acorn GXR Rom re-create that?'. I have arrived!