extract Planes from an rectangular entity

Hi,
IS it possible to extract all Planes from an rectangular entity?

Here is my rectangular and I want to extract its planes

How can I do it?

var greenRectangle = viewer.entities.add({

name : ‘Green translucent, rotated, and extruded rectangle at height with outline’,

rectangle : {

coordinates : Cesium.Rectangle.fromDegrees(-100.0, 30.0, -90.0, 40.0),

material : Cesium.Color.GREEN.withAlpha(0.5),

rotation : Cesium.Math.toRadians(45),

extrudedHeight : 300000.0,

height : 100000.0,

outline : true,

outlineColor : Cesium.Color.GREEN

}

});

``