import megamu.shapetween.*;

BackShaper back;
Tween punch;

void setup(){
  size(200,200);
  punch = new Tween(this, 0.5);
  punch.setPlayMode( Tween.REVERSE_REPEAT );
  back = new BackShaper();
  punch.setEasing(back);
}

void draw(){
  background(255);
  
  back.setAnticipation( norm(mouseX, 0, width) );

  float ant = lerp(75, 150, -back.getAnticipation());
  line( ant, 30, ant, 170 );
  line( 160, 20, 160, 180 );
  ellipse( lerp(75, 150, punch.position()), 100, 20, 20 );
}