  color: DC.Color.YELLOW,
          speed: 10,
        }),
        clampToGround: true,
      })

      let polyline3 = new DC.Polyline('-80, 30; -75, 30').setStyle({
        width: 5,
        material: new DC.PolylineFlowMaterialProperty({
          color: DC.Color.GREEN,
          speed: 10,
        }),
        clampToGround: true,
      })

      layer
        .addOverlay(polyline)
        .addOverlay(polyline1)
        .addOverlay(polyline2)
        .addOverlay(polyline3)
      viewer.flyTo(layer)
    <