// declare objects Ball ball1; Ball ball2; Ball ball3; Ball ball4; // initialize variables float gravity = 0.1; // gravity! void setup() { size(400,400); ellipseMode(CORNER); ball1 = new Ball(color(255,0,0,50),20); ball2 = new Ball(color(0,0,255,50),50); ball3 = new Ball(color(0,255,0,50),100); ball4 = new Ball(color(255,0,255,50),150); smooth(); } void draw() { background(255); ball1.display(); ball1.move(); ball2.display(); ball2.move(); ball3.display(); ball3.move(); ball4.display(); ball4.move(); }