Some shapes but not all can be rotated
Shapes do not apply to obects that contain a picture
You can select two shapes. After you select the first shape hold down Ctrl and select second shape.
The second shape is then overlaid on the first shape, so you can have Diamonds in Circles and other compound shapes.
You can also have a double line in a symbol. This combined with the Split tag text placement provides for tags that look very much like those on typical P&IDs. See also Tag Balloons