Geometric algebra: geometry of bivectors and bivector factorization

In this video, I
* show how multiplication of a vector in a plane, by a bivector for that plane, rotates that vector 90 degrees,
* compute the projection and rejection of a vector with respect to the plane represented by a bivector B, showing that those components are perpendicular.
* show that x . B lies in the plane of B, rotated 90 degrees from the projection of x onto B.
* show that x is perpendicular to x . B
* show that x . B = n cross x, if B = I n (i.e.: n is normal to the plane)
* illustrate how to find vector factors of a bivector using bivector multiplication, and the dual form with cross products with the normal to the plane.