Using Loops to Make Objects. Help!

Processing Coding Questions
5

void setup()
{
size (400,400);
smooth();
}
int diam = 20;
int x1 = 10;
int y1 = 10;
int x2 = 50;
int y2 = 50;
int x3 = 90;
int y3 = 90;
int xDir = 1;
int yDir = 1;
int xDir2 = 1;
int yDir2 = 1;
int xDir3 = 1;
int yDir3 = 1;
int r, g, b;

void draw()
{
background(r, g, b);

fill(255 - (x1 + y1) * .6375 / 2);
ellipse(x1, y1, diam, diam);

fill(255 - (x2 + y2) * .6375 / 2);
ellipse(x2, y2, diam, diam);

fill(255 - (x3 + y3) * .6375 / 2);
ellipse(x3, y3, diam, diam);

if(x1 > width - diam / 2 || x1 < diam / 2)
{
xDir = -xDir;
}
if(x2 > width - diam / 2 || x2 < diam / 2)
{
xDir2 = -xDir2;
}
if(x3 > width - diam / 2 || x3 < diam / 2)
{
xDir3 = -xDir3;
}

if(y1 > height - diam / 2 || y1 < diam / 2)
{
yDir = -yDir;
}
if(y2 > height - diam / 2 || y2 < diam / 2)
{
yDir2 = -yDir2;
}
if(y3 > height - diam / 2 || y3 < diam / 2)
{
yDir3 = -yDir3;
}

x1 = x1 + xDir;
y1 = y1 + yDir;
x2 = x2 + xDir2;
y2 = y2 + yDir2;
x3 = x3 + xDir3;
y3 = y3 + yDir3;
}

void keyPressed()
{
if(key == ENTER || key == RETURN)
{
r = (int) random(255);
g = (int) random(255);
b = (int) random(255);
}
}