This project is pretty simple:
When the "Pencil" tool is selected, you will be able to draw on one side, and have the same drawing come up on the other side! When the "Eraser" tool is selected, you will be able to erase lines, without it erasing on both sides! You can change the size of the pen or eraser, as well as clear the entire screen!
This is just something I came up with and made pretty quickly. There may be some glitches, but if you let me know what they are, I will be happy to try and fix them!