class Particle {
  Vector3D      pos;     // position
  Vector3D      vel;     // velocity
  Vector3D      force;   // force
  float         mass;    // mass
  boolean       bAlive;  // alive or dead
  boolean       fixed;  // fixed or free

  Particle() {
    bAlive = false;
    pos   = new Vector3D(0,0,0);
    vel   = new Vector3D(0,0,0);
    force = new Vector3D(0,0,0);
    bAlive = true;
  }

  void set(Particle p) {
    pos.set(p.pos);
    vel.set(p.vel);
    force.set(p.force);
    this.bAlive = p.bAlive;
    this.fixed = p.fixed;
  }

  void setPropertiesAndTurnOn(Vector3D posIn, Vector3D velIn) {
    bAlive = true;
    pos.set(posIn);
    vel.set(velIn);
  }


  void draw() {
    fill(0);
    noStroke();
    ellipseMode(CENTER);
    ellipse(pos.x, pos.y, 10,10);
  }

}