import megamu.shapetween.*;
Tween ani;
void setup(){
ani = new Tween(this, 2);
ani.setPlayMode( Tween.REVERSE_REPEAT );
ani.start();
}
void draw(){
background(255);
ellipse(ani.time()*width, ani.position()*height, 4, 4);
}
void mousePressed(){
ani.setPlayMode( Tween.ONCE );
}
setPlayMode(mode)