// camera with sky vector (tilt)  ------------------
camera{ location < 3.00,  3.50,-5.00>
        angle    40
        sky       <0.5, 1.0,  0.0>        // direction of the camera "sky"
        right    x*image_width/image_height
        look_at  < 0.00,  1.00, 0.00> 
     } // -------------------------------------------
//---------------------------------------------------