simonrockman said 
Hi This is *exactly* what I was after. What are the fonts which support this?
I can't name any fonts right now but google 'contextual alternates' and I'm sure you will find some in the tutorials about this feature.
Glad I could be of help! Have fun with that Axidraw of yours!

claudeserieux said 
Typesgal said 
Not sure what you mean by 'changing as you use it' but if I think right that can be an Opentype font with contectual alternates and/or contectual ligatures features. These kind of fonts contain multiple variations for letters and ligatures and use them variably throughout the text. In other words you get different looks for the same letters. Be aware that bringing these features live requires a software that supports them.
Import .svg sur Inkscape pour Axidraw

He did not ask about how to use Axidraw.
Not sure what you mean by 'changing as you use it' but if I think right that can be an Opentype font with contextual alternates and/or contextual ligatures features. These kind of fonts contain multiple variations for letters and ligatures and use them variably throughout the text. In other words you get different looks for the same letters. Be aware that bringing these features live requires a software that supports them.
Hope I could help you out!
Edited on Aug 11, 2016 at 18:32 by Typesgal
Not just the delay, but he didn't even uploaded all submissions. At least mine isn't on the new list...
All times are CEST. The time is now 10:22