class MyElement{
    int diameter = 5;
    float xpos = 0.; 
    float ypos = 0.; //position
    float friction = 0.5;
    float xspeed = 0; 
    float yspeed = 0; // speed
    void move() {
      xpos += (xspeed/friction);
      ypos += (yspeed/friction);
      if (xpos > width) xspeed *= -1;
      else if (xpos < 0) xspeed *= -1;
      if (ypos > height) yspeed *= -1;
      else if (ypos < 0) yspeed *= -1;
      xpos = constrain(xpos, 0, width);
      ypos = constrain(ypos, 0, height);
      ellipse(int(xpos),int(ypos),diameter,diameter);
      friction += 0.01;
    }
  }