#A note on the setup() function setup() is called once when the program starts and should not be called again. setup() can set the screen size and background colour. There can only be one setup() function for each sketch.
#A note on the draw() function You should never call the draw() function. Processing automatically calls the draw() function straight after the setup() call. draw() continuously executes the code contained inside it. There can only be one draw() function for each sketch.