BUTTONS -- Practice (Explained)

So my goal for this project was to create more of an abstract design. I wanted to place rectangles of different sizes around my sketch. The plan was to have the rectangles be the buttons. If you click a button (rectangle), you change the background of the sketch. The buttons would already be different colors so you'd be able to tell what you would get out of it; except a shade lighter or darker. I ran into trouble with this, so what I had down (not finished) wasn't able to load. But I saved that and thought I'd post it anyways.