void setup(){
size(400, 400);
frameRate(30);
}

void draw() {
 background(220); // Set background color
  
// Using stroke() and fill()
  stroke(0); // Set outline color to black
  
  fill(255, 0, 0); // Set fill color to red
  rect(20, 20, 50, 50);
  
  fill(0, 255, 0); // Set fill color to green
  stroke(255, 0, 0); // Set outline color to red
  rect(90, 20, 50, 50);
  
  noFill(); // No fill
  stroke(0, 0, 255); // Set outline color to blue
  rect(160, 20, 50, 50);
  
  noStroke(); // No outline
  fill(0, 0, 255, 100); // Set fill color to blue with transparency
  ellipse(50, 150, 80, 80);
  
  // Using noStroke() and noFill()
  stroke(0); // Set outline color to black
  fill(255); // Set fill color to white
  
  rect(230, 20, 50, 50);
  
  noStroke(); // No outline
  noFill(); // No fill
  rect(290, 20, 50, 50);
}