Source Code:

int angle = 0;
int size = 0;
int inside_stroke = 160;
int outside_stroke = 60;
void setup() {
  size(640, 360);
  background(102);
  smooth();
  noStroke();
  fill(0, 102);
}

void draw() {
  // Draw only when mouse is pressed
  if (mousePressed == true) {
    angle += 10;
    size += 1;
    float val = cos(radians(angle)) * 6.0;
    for (int a = 0; a < 720; a += 75) {
      a = a + (size / 2 );
      float xoff = cos(radians(a)) * (val+size);
      float yoff = sin(radians(a)) * (val+size);

      stroke(outside_stroke);
      outside_stroke +=1;
      if (outside_stroke > 127) {
         outside_stroke = 60;
      }
      fill(0);
      ellipse(mouseX + xoff, mouseY + yoff, val+size, val+size);
      if (size > 20) {
        size = 1;
      }
    }
    inside_stroke +=1;
	if (inside_stroke > 255) {
       inside_stroke = 165;
    }
    stroke(inside_stroke);
    fill(255);
    ellipse(mouseX, mouseY, 2+size/2, 2+size/2);
  } else {
    size = 0;
  }
}

Inspired by http://processing.org/learning/topics/pulses.html