public Particle(Point20 p, Point20 v, Point20 a, int index)
{
P = p;
V = v;
A = a;
Index = index;
}
public static Point20 operator +(Point20 c1, Point20 c2)
{
var p = new Point20(c1.X + c2.X, c1.Y + c2.Y, c1.Z + c2.Z);
return(p);
}