requested by misha. quick sketch

Star.pde

class Point {
  int xcor, ycor;
  Point(int x, int y) {
    xcor = x;
    ycor = y;
  }
  String toString() {
    return "("+xcor+","+ycor+")";
  }
}

class Star {
  Point center;
  int xrad;
  int yrad;
  Point top;
  Point right;
  Point bottom;
  Point left;
  Star(Point c, int radius) {
    center = c;
    xrad = radius;
    yrad = radius;
    top = new Point(center.xcor, center.ycor-yrad);
    bottom = new Point(center.xcor, center.ycor+yrad);
    left = new Point(center.xcor-xrad, center.ycor);
    right = new Point(center.xcor+xrad, center.ycor);
  }
  Star(Point c, int xr, int yr) {
    center = c;
    xrad = xr;
    yrad = yr;
    top = new Point(center.xcor, center.ycor-yrad);
    bottom = new Point(center.xcor, center.ycor+yrad);
    left = new Point(center.xcor-xrad, center.ycor);
    right = new Point(center.xcor+xrad, center.ycor);
  }
  void drawS() {
    drawArc(center, top, right);
    drawArc(center, bottom, right);
    drawArc(center, left, bottom);
    drawArc(center, left, top);
  }
  String toString() {
    return "xrad:"+xrad+", yrad:"+yrad+"centered at:"+center;
  }
  void drawArc(Point center, Point p1, Point p2) {
    int c1x, c1y, c2x, c2y;
    int h = (p1.xcor == center.xcor) ? (p2.xcor) : (p1.xcor);
    int k = (p1.ycor == center.ycor) ? (p2.ycor) : (p1.ycor);
    int DY = (k < center.ycor) ? -3*xrad : 3*xrad;
    if (h > center.xcor) {
      c1x = center.xcor;
      c1y = k+DY;
      c2x = h+(3*yrad);
      c2y = center.ycor;
    } else {
      c1x = h+(-3*yrad);
      c1y = center.ycor;
      c2x = center.xcor;
      c2y = k+DY;
    }
    stroke(255);
    curve(c1x, c1y, p1.xcor, p1.ycor, p2.xcor, p2.ycor, c2x, c2y);
  }
}

twinklingStars.pde

/*
a night sky of twinkling stars
*/
int w = 200;
int h = 200;
color c = color(255);
ArrayList<Star> galaxy = new ArrayList<Star>();
int numStars = (int)(Math.random()*w+(w/2));

void setup() {
  size(w,h);
  background(0);
  for (int i = 0; i < numStars; i++) {
    //gneerate a random point to make a star and push into galaxy
    /*
      http://stackoverflow.com/questions/7922978/random-numbers-with-math-random-in-java
      always need a resource when dealing with random nums because i'm stupid
    */
    //random yrad
    int yrad = (int)(Math.random()*5+5);
    //random xrad. because i don't want stupid looking stars, im restricting this to be smaller than the y
    int xrad = (int)(Math.random()*yrad+1);
    //random xcor and ycor of central pt
    int x = (int)(Math.random()*(w-2*xrad)+xrad);
    int y = (int)(Math.random()*(w-2*yrad)+yrad);
    Star s = new Star(new Point(x,y), xrad, yrad);
    galaxy.add(s);
  }
}

void draw() {
  background(0);
  //now we make them twinkle
  int mod = (int)(Math.random()*(galaxy.size()/7)+1);
  for (int i = 0; i < galaxy.size(); i++) {
    if (i%mod == 0) {
      Star current = galaxy.get(i);
      current.drawS();
    }
  }
}