//wrap around so it cannot get too far away
//get the vector from dla_center to current_circle
PVector center_to_circle = PVector.sub(current_circle,dla_center);
float sq_dist = sq(center_to_circle.x)+sq(center_to_circle.y);
if(sq_dist > bound_radius_sq) {
  float prev_dist = sqrt(sq_dist);
  //make the distance outside of the radius into the amount inside
  //bound_radius-(prev_dist-bound_radius)
  float new_dist = 2*bound_radius-prev_dist;
  center_to_circle.mult(-new_dist/prev_dist);
  current_circle.x = center_to_circle.x+dla_center.x;
  current_circle.y = center_to_circle.y+dla_center.y;
}