A bivector is a wedge product of two independent vectors which can be imagined as a parallelogram and a trivector is a wedge product of three independent vectors which can be imagined as a paralleopiped. So am I correct in thinking that this parallelogram and paralleopiped is the bivector and the trivector itself, respectively? (With its magnitude as the area and the volume, respectively?). If so how can you imagine the orientation of a bivector? (its even more harder to imagine the orientation of a trivector!).