necking.pde

int strokeFrames = 100;
int strokeCount = 0;
int saveFrame = 1;
boolean up = true;

void setup() {
  size(500, 500);
}

void draw() {
  background(255);
  int x = 65;
  int y = -65;

  noFill();
  stroke(0);
  strokeWeight(20);
  
  if (up) {
    rect(20+x, 230+y, 250, 250);  
    line(270+x, 230+y, 370+x, 130+y);
    redline();
    rect(120+x, 130+y, 250, 250);
    line(20+x, 223+y, 112+x, 130+y);  
    line(20+x, 480+y, 120+x, 380+y);
    line(276+x, 480+y, 370+x, 386+y);
  } else {
    rect(120+x, 130+y, 250, 250);
    line(20+x, 223+y, 112+x, 130+y);  
    line(20+x, 480+y, 120+x, 380+y);
    line(276+x, 480+y, 370+x, 386+y);
    redline();
    rect(20+x, 230+y, 250, 250);  
    line(270+x, 230+y, 370+x, 130+y);
  }
  if (strokeCount == 1 || strokeCount == 2) {
    String fname = nf(saveFrame, 3) + ".png";
    save(fname);
    saveFrame++;
    println(fname);
  }
}

void redline() {
  pushMatrix();
  translate(width*0.5, height*0.5);
  rotate(PI*0.25);
  noStroke();
  float n = norm(frameCount % strokeFrames, 0, strokeFrames);
  float t = (1.0 - cos(n*TWO_PI)) * 0.5;
  if (frameCount % strokeFrames == 0) {
    up = !up;
    strokeCount++;
  }
  fill(255, 0, 0);
  rectMode(RADIUS);
  rect(0, 0, 25+140*t, 25+140*t);
  popMatrix();
  noFill();
  stroke(0);
  strokeWeight(20);
  rectMode(CORNER);
}