strokeWeight(2);
arc(50, 55, 50, 50, 0, HALF_PI);
arc(50, 55, 60, 60, HALF_PI, PI);
arc(50, 55, 70, 70, PI, TWO_PI - HALF_PI);
noFill();
arc(50, 55, 80, 80, TWO_PI - HALF_PI, TWO_PI);