Click the applet, if the keys don't work.
Instructions:
To change the Background, draw in a different Colour or use a "Stamp" you must hold down the B, C or S buttons.
To change background, hold down "B" and press any number 0-9.
To change colour hold down "C" and press any number 0-9.
To use a stamp hold down "S" and press any number 0-9.
Pressing "E" erases everything.