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;
  }
}