I decided to look at what the pen could do, so I made this simple project. I always clean my code up so you can see how my projects work - so feel free to use any of these scripts. If you have any suggestions just put them in the comments. Also if you've made a cool color that you want to be in the palette, put the code and name in the comments. I purposely spelt colour wrong for Americans.
Credit to dr3w8 for the custom blocks. updates: v1.2 (18 Feb 2015) fixed a bug. v1.1 (11 Nov 2014): Added custom color creator! Create and name your color. Press the green ... button to see your custom color and more colors that I'll be adding soon. (Note: typing a word, letter or nothing in the box when it asks you for the color number will make it stay red.) Also now the colors tell you what they are when you hover over them, which was why I added the custom color naming bit. Hovering over Create color will show a list of the already existing colors. Brush size and Clear buttons hide when looking at other colors and show when you click back. Press a to bring up the code and press b to close it.