I need the rects on the left of the screen to move on the X coordinate in accordance to the spring over them. Anyone know a simple way to do that? I'm very new so as simplistic answer would be great. I'm thinking of making 3 more rects under the 3 I already have that match the background (making them invis) then having the white rects move using a PVector that changes the length of them when the spings are over the invis rects.

int num = 6;
Spring[] springs = new Spring[num];
int pop[];

void setup()
{
  size(700, 500);
  noStroke();

 springs[0] = new Spring(460, 410,  30, 0.98, 8.0, 0.08, springs, 0);
 springs[1] = new Spring(460, 340, 30, 0.95, 9.0, 0.1, springs, 1);
 springs[2] = new Spring(460, 270, 30, 0.90, 9.9, 0.1, springs, 2);
 springs[3] = new Spring(460, 200,  30, 0.98, 8.0, 0.08, springs, 3);
 springs[4] = new Spring(460, 120,  30, 0.98, 8.0, 0.08, springs, 4);
 springs[5] = new Spring(460, 40,  30, 0.98, 8.0, 0.08, springs, 5); 
}

void draw()
{
  background(51);
 
  for (int i = 0; i < num; i++) {
    springs[i].update();
    springs[i].display();
  }
  stroke(20);
  fill(255,255,255);
  rect(0,0,400,160);
  rect(0,160,400,150);
  rect(0,310,400,140);
}

void mousePressed()
{
  for (int i = 0; i < num; i++) {
    springs[i].pressed();
  }
}

void mouseReleased()
{
  for (int i=0; i<num; i++) {
    springs[i].released();
  }
}

class Spring
{
 
  float xpos, ypos;
  float tempxpos, tempypos;
  int size = 20;
  boolean over = false;
  boolean move = false;


  float mass;      
  float k = 0.2;   
  float damp;      
  float rest_posx;
  float rest_posy; 

 
  float velx = 0.0;  
  float vely = 0.0;  
  float accel = 0;   
  float force = 0;   

  Spring[] friends;
  int me;
 
 
  Spring(float x, float y, int s, float d, float m,
         float k_in, Spring[] others, int id)
  {
    xpos = tempxpos = x;
    ypos = tempypos = y;
    rest_posx = x;
    rest_posy = y;
    size = s;
    damp = d;
    mass = m;
    k = k_in;
    friends = others;
    me = id;
  }

  void update()
  {
    if (move) {
      rest_posy = mouseY;
      rest_posx = mouseX;
    }

    force = -k * (tempypos - rest_posy);
    accel = force / mass;                 
    vely = damp * (vely + accel);        
    tempypos = tempypos + vely;           

    force = -k * (tempxpos - rest_posx);
    accel = force / mass;                
    velx = damp * (velx + accel);        
    tempxpos = tempxpos + velx;          

   
    if ((overEvent() || move) && !otherOver() ) {
      over = true;
    } else {
      over = false;
    }
  }
 
 
  boolean overEvent() {
    float disX = tempxpos - mouseX;
    float disY = tempypos - mouseY;
    if (sqrt(sq(disX) + sq(disY)) < size/2 ) {
      return true;
    } else {
      return false;
    }
  }
 
 
  boolean otherOver() {
    for (int i=0; i<num; i++) {
      if (i != me) {
        if (friends[i].over == true) {
          return true;
        }
      }
    }
    return false;
  }

  void display()
  {
    if (over) {
      fill(153);
    } else {
      fill(255);
    }
    ellipse(tempxpos, tempypos, size, size);
  }

  void pressed()
  {
    if (over) {
      move = true;
    } else {
      move = false;
    } 
  }

  void released()
  {
    move = false;
    rest_posx = xpos;
    rest_posy = ypos;
  }
}