Attractor Each circle on the grid points change its diameters, which based on distance between mouse position and point’s location. Dictionary: Attractor 吸引子，原本為複雜科學裡的一個專有名詞，近期廣被用來描述於Parametricism。 最先被運用在Grasshopper裡頭。

int space = 20;
int shiftX; 
int shiftY; 

void setup() {
  size(650, 450);
  smooth();
  shiftX = (width % space)/2;
  shiftY = (height % space)/2;
}

void draw() {
  background(200);

  for (float x = space-shiftX; x < width; x+=space) {
    for (float y = space-shiftY; y < height; y+=space) {

      line(x, 0, x, height);

      float rad = dist(mouseX, mouseY, x, y);
      stroke(rad, rad, rad);
      ellipse(x, y, rad/(1.5*space), rad/(1.5*space)); 
    }
  }
}