rdinates': [[-5e6, -5e6], [0, -5e6]]
            }, {
              'type': 'Point',
              'coordinates': [4e6, -5e6]
            }, {
              'type': 'Polygon',
              'coordinates': [[[1e6, -6e6], [2e6, -4e6], [3e6, -6e6]]]
            }]
          }
        }]
      };

      var vectorSource = new ol.source.Vector({
        features: (new ol.format.GeoJSON()).readFeatures(geojsonObject)
      });

      vectorSource.addFeature(new ol.Feature(new ol.geom.Circle([5e6, 7e6], 1e6)));

 