Background and Text Colors

This applet illustrates:

init, actionPerformed and paint in one applet. The applet has two buttons which, when pressed, change the colors of the objects drawn on the screen.
The use of several class variables, to keep track of the color of the background and of the text being painted on the screen.
The use of the switch statement, instead of several if's and else's.
The use of the mod function (counting an integer modulo s fixed value). This is used to cycle through several values.