void setup(   ){
  size(1000, 1000);
  background(255, 255, 255);
}

Boolean roundBall = true;
float x = 100, y = 100;
float vx = 0, vy = 0;
float ax = 0, ay = 0;
float gravity = 0.1;
void draw(){
   ax = (mouseX - x) * 0.005;
   ay = (mouseY - y) * 0.005 + gravity; 
   background(255, 255,255);
   
   fill(200, 0, 0);
//   stroke(0, 255, 0); // This changes the line and outline colors
   line(mouseX, mouseY, x, y);
//   stroke(0, 0, 255);
   if(roundBall){
     ellipse(x, y, 40, 40);
   } else {
     rect(x, y, 40, 40); 
   }
   x += vx;
   y += vy;
   vx += ax;
   vy += ay;
   vx *= 0.995;
   vy *= 0.995;
}

void mousePressed(){
   background(255, 255, 255); 
}

void keyPressed(){
    if(key == 's'){
       roundBall = !roundBall;
    }
}