splitCircle

color bg = #95729C;
color str = #B7AACF;
float theta, arcFin, diam, num;

void setup() {
  size(500, 500);
  background(bg);
  noFill();
  stroke(str);
  strokeCap(SQUARE);
  diam = 200;
  num = 2;
}
void draw() {

  background(bg);

  for (int i=0; i<num; i++) {
    float step = TAU/num;
    arcFin = map(sin(theta), -1, 1, i*step+ radians(1), i*step + step + radians(-2));
    float sw = map(sin(theta), -1, 1, 20, 50 );
    strokeWeight(sw);
    arc(width/2, height/2, diam, diam, i*step, arcFin);
  }

  theta += 0.0523;

  if (frameCount % 2 == 0 & frameCount<121) saveFrame("image-####.gif");
}