void setup() {
size(600 , 400);
palette = rolandgarros;
int numSpots = 50; // Number of objects
int dia = (width-20)/numSpots; // Calculate diameter
spots = new Spot[numSpots]; // Create array
for (int i = 0; i < spots.length; i++) {
float x = 20+dia/2 + i*(dia);
float rate = random(1.0, 3.0);
// Create each object
spots[i] = new Spot(x,30, dia, rate);
}
noStroke();
}
void draw() {
// the orange ground background, with increasing alpha
fill(palette[0], 12);
rect(10, 10, width-20, height-20);
// the white line
fill(palette[5], 100);
rect(10,10+(height-10)/2, width-20, 10);
// the green borders
fill(palette[2]);
rect(0,0,width, 10);
rect(0,height-10,width, 10);
rect(0,0,10, height);
rect(width-10,0,10, height);
//the bouncing balls
fill(palette[4]);
for (int i=0; i < spots.length; i++) {
spots[i].move(); // Move each object
spots[i].display(); // Display each object
}
}

class Spot {
float x, y;
float diameter;
float speed;
int direction = 1; // Direction of motion (1 is down, -1 is up)

// Constructor
Spot(float xpos, float ypos, float dia, float sp) {
x = xpos;
y = ypos;
diameter = dia;
speed = sp; }
void move() {
y += (speed * direction);
if ((y > (height-10 - diameter/2)) || (y < 10+diameter/2)) {
direction *= -1;
}
}
void display() {
ellipse(x, y, diameter-1, diameter-1);
}