public MyVector2D Subtract(MyVector2D v)
{
x -= v.x;
y -= v.y;
return this;
}
public MyVector2D(MyVector2D v)
{
x = v.x;
y = v.y;
}
public MyVector2D Add(MyVector2D v)
{
x += v.x;
y += v.y;
return this;
}
