Vector code now works with Fractions .. but slower

@@ -344,8 +344,13 @@ fn main() {
 
     let tetrahedron = Polyeder::tetrahedron(60.0);
     let        cube = Polyeder::cube(60.0);
-    let      camera = Camera::<f64>::new(&canvas, 40); // the orig. view angle
+    let      camera = Camera::<f64>::new(&canvas, 45); // the orig. view angle
                                                        // was 50.
+    /*
+    let tetrahedron = Polyeder::tetrahedron(Fractional(60,1));
+    let        cube = Polyeder::cube(Fractional(60,1));
+    let      camera = Camera::<Fractional>::new(&canvas, 45);
+    */
 
     canvas.start_events(tx);
 
@@ -355,21 +360,28 @@ fn main() {
     thread::spawn(move || {
         loop {
             let deg = ((start.elapsed() / 25).as_millis() % 360) as i32;
-            let rot1 :TMatrix<f64> = rotate_z(deg)
-                                   * rotate_x(-deg*2)
-                                   * translate(Vector(0.0, 0.0, 150.0));
 
-            let rot2 :TMatrix<f64> = rotate_z(-deg*2)
-                                   * rotate_y(deg)
-                                   * translate(Vector(0.0, 0.0, 150.0));
+            let t = translate(Vector(0.0, 0.0, 150.0));
+            let rz :TMatrix<f64> = rotate_z(deg);
+            /*
+            let t = translate(Vector( Fractional(0,1)
+                                    , Fractional(0,1)
+                                    , Fractional(150,1) ));
+            let rz :TMatrix<Fractional> = rotate_z(deg);
+            */
+
+            let rot1 = TMatrix::combine(vec!(rz, rotate_x(-deg*2), t));
+            let rot2 = TMatrix::combine(vec!(rz, rotate_y(-deg*2), t));
+
+            let objects = vec!( (tetrahedron.transform(&rot1), 0xFFFF00)
+                              , (       cube.transform(&rot2), 0x0000FF) );
 
             canvas.clear();
 
-            for pg in tetrahedron.transform(&rot1).project(&camera) {
-                canvas.draw(&pg, Coordinate(0,0), 0xFFFF00);
-            }
-            for pg in cube.transform(&rot2).project(&camera) {
-                canvas.draw(&pg, Coordinate(0,0), 0x0000FF);
+            for (o, color) in objects {
+                for pg in o.project(&camera) {
+                    canvas.draw(&pg, Coordinate(0,0), color);
+                }
             }
 
             let passed = Instant::now() - last;