public class Particle{
    public double x;
    public double y;
    private Gas appletref;

 
  Particle(){}


    public void MovePart(double iwidth, double jwidth, double ex, double ey){
      x=(x+ex);
      if (x>iwidth){
        x=x-iwidth;
      }
      if (x<0){
        x=x+iwidth;
      }

      y=(y+ey);
      if (y>jwidth){
        y=y-jwidth;
      }
      if (y<0){
        y=y+iwidth;
      }
    }
  }