Hi ! It is very common for graphical libraries to declare some rectangle and point classes. In fact, all of them do that: SDL has SDL_Rect, X has XRectangle and XPoint, Qt has QRect and QPoint, Window$ has POINT and RECT (and POINTF and RECTF), rect, Rect, Rectangle, point, Point2D, Point3D, point<float> ..... etc .... And you know what ? they all are incompatible, both interface and implementation. Time to have a look at this, heu ? After few months of work here is what I have: // Code Start int main() { // point_xy is an implementation type it contains // "some implementation" of the point abtraction // Other implementaions include point_xyz<>, for 3D points typedef geom::point_xy<double> point_xy; // point<> is a wrapper class, in which you "plug" implementation types // to obtain a working ``point'' typedef geom::point<point_xy> point; // Plug, then save the result in ``point'' point pt=point_xy(3.4, 3.0), pt2=point_xy(0.2, 1.4); // Cool property access pt.x()++; pt.y()=pt2.rho(); pt.theta()+=3*pt2.y(); // Handy operator overloads pt+=pt2*4; // std::complex<> is also a possible implementation geom::point< std::complex<double> > pt_cplx=std::complex<double>(4, 6); pt2=pt_cplx-pt; // Mixed-implementation computations // point::impl() extracts the implementation out of its wrapper std::complex<double>& impl=pt_cplx.impl(); // Now for Boxes. Boxes are some generalization of rectanlges that are not always // ``flat'' typedef geom::box_xywh<int> box_xywh; // Implementation type .. typedef geom::box<box_xywh> box; // .. being plugged in a wrapper box bx, bx2; bx.xmin()=bx2.x2(); bx.width()=bx2.height(); bx.y2()=bx2.height(); // Accessing corners bx.corner< geom::x1, geom::y1>()=pt; // Displace bx.corner< geom::xmin, geom::ymax >()=bx2.corner<geom::x2, geom::y1, geom::z1>(); // Accessing the center bx.center()=bx2.center()+pt; bx2.x1()=bx.center().x(); // ..... } // Code End So, wadda you say ? -- Anis Benyelloul