**Request** - if you start the stroke on the 2nd colour, or no colour, then the 1st colour is drawn - if you start the stroke on the 1st colour the 2nd colour is drawn So, this is a pen that operates with XOR function. **Benefits** - reduce need to swap between selected colours - reduce need to swap between pen and eraser - for drawing in only black and white you never have to swap colours or tools at all! **Example** - ResEdit https://twitter.com/gingerbeardman/status/1786504929730838958 **Try it yourself** I added this as the default tool in my build of Piskel: https://github.com/gingerbeardman/piskel-playdate