Processing Circles

import java.util.Random;

Random generator; 

void setup() {
  size(1120,1200);
  generator = new Random();
  background(50);
}

void draw() {
  float numX = (float) generator.nextGaussian();
  float numY = (float) generator.nextGaussian();
  float sd = 70;
  float mean = 320;
  float x = sd * numX + mean;
  float y = sd * numY + mean;
  noStroke();
  fill(250, 10);
  ellipse(x, y, 900, 900);
}

Processing Circles, random green

import java.util.Random;

Random generator; 

void setup() {
  size(1120,1200);
  generator = new Random();
  background(250);
}

void draw() {
  float numX = (float) generator.nextGaussian();
  float numY = (float) generator.nextGaussian();
  float sd = 70;
  float mean = 320;
  float x = sd * numX + mean;
  float y = sd * numY + mean;
  
  if (random(1) > 0.9) {
    noStroke();
    fill(random(160), random(200), random(2), 10);
    ellipse(x, y, 900, 900);
  }
}