MOBILE mode: Click the things at the bottom of the screen to change colour or to erase or clear your drawing. Use slider to change the width of your pen. COMPUTER mode: Use numbers on keyboard to select colour or erase or clear your drawing. Use arrow keys to change the width of your pen.
Thanks to @AmblerCodingTeacher for setting me this task. Thanks to @auton14 for the idea of a rainbow paint bucket. Thanks to RPiFoundation for the tutorial at: https://projects.raspberrypi.org/en/projects/paint-box
