title: how to display multiple polylines from directions in google maps?
body: <p>i want to draw multiple polylines on the google map, for multiple routes.
  for this i am using <code>google.maps.DirectionsService</code></p>
  
  <pre><code>function drawPolyline(source,destination,waypoints){
          // show route between the points
          directionsService = new google.maps.DirectionsService();
          directionsDisplay = new google.maps.DirectionsRenderer(
          {
              suppressMarkers: true,
              suppressInfoWindows: true
          });
          directionsDisplay.setMap(map);
          var request = {
              origin:source, 
              destination:destination,
              waypoints:waypoints,
              travelMode: google.maps.DirectionsTravelMode.DRIVING
          };
          directionsService.route(request, function(response, status) 
          {
              if (status == google.maps.DirectionsStatus.OK) 
              {
                  directionsDisplay.setDirections(response);
  
              }
          });
  
        }
  </code></pre>
  
  <p>but when i call this method multiple times, only last polyline is appearing.
  and i want different colors for different polylines.</p>