In this demonstration, it is possible to change the positions of the three vectors, A, colored red, B, colored green, and C, colored yellow, by clicking and dragging the heads of the vectors. This will move each of them within the viewing plane. To change the viewing plane, select Rotate from the Tools menu and click and drag anywhere in the viewing window. The plane given by A + sB + tC, with s and t each going from 0 to 1, is shown in gray. The plane through the origin parallel to this plane, given by sB + tC, is also shown in gray.