+\parbox{11cm}{
+\centerline{Master coordinate (MC) level}
+\centerline{$\downarrow$}
+\centerline{Apply \emph{Current transformation matrix}}
+\centerline{$\downarrow$}
+\centerline{World coordinate (WC) level}
+\centerline{$\downarrow$}
+\centerline{Clipping against Window}
+\centerline{$\downarrow$}
+\centerline{Convert to Normalized device coordinates (NDC)}
+\centerline{$\downarrow$}
+\centerline{Clipping against Viewport}
+\centerline{$\downarrow$}
+\centerline{Convert to Physical device coordinates (PDC)}
+}