Chaotic Maps in Processing 3, The Business Cycle Map

The pattern is generated with the following code:

//Attractors
float a = 1;
float b = a;
//Initial values
float x = 0.125;
float y = x;
void setup() {
  frameRate(60);
  size(800,600);
  colorMode(RGB, 255, 255, 255);
  background(0);
  stroke(255, 255, 255);
  strokeWeight(0/125);
}
void draw() {
  float dx = x + y;
  float dy = (a * y) - (a + 1) * pow(y, 3) - (b * x);
  x = dx;
  y = dy;
  translate(width / 2, height / 2);
  point(x * 80, y * 80);
}

It creates the following image: