rotRect

float r= 0;
float r2=PI;
float s = 40;
int sz=80;
boolean saveAnim = false;
float frm;

void setup() {
  size(500, 500);
  background(#202020);
  fill(#202020, 100);
  stroke(255);
}

void draw() {

  translate(width/2, height/2);

  pushMatrix();
  rotate(r2);
  rect(s-sz/2, 0, sz*.75, sz*.75, 10);
  popMatrix();

  pushMatrix();
  rotate(r);
  rect(s, 0, sz, sz, 10);
  popMatrix();

  pushMatrix();
  rotate(r2);
  rect(s+sz/2, 0, sz*1.25, sz*1.25, 10);
  popMatrix();

  r += TAU/90;
  r2 -= TAU/90;

  if (saveAnim) {
    if (frameCount % 3 == 0 && frameCount < frm+91) saveFrame("image-###.gif");
  }
}

void keyPressed() {
  saveAnim = true;
  frm = frameCount;
}