Projection Animation of F4

Figure 24. Animation of $F_4$, projecting along the direction $p_\theta = \cos(\theta)r^1 + \sin(\theta)r^4$ which is confined to a plane in $\mathbf{R}^4$ containing $r^1$ and $r^4$.
Press '<CTRL>-A' to start display the controls for this animation.

This is a three-dimensional projection of a four-dimensional root diagram, where the projection is confined to a plane. Hence, there is a plane in this figure which is not affected by the projection. Try turning the diagram to find this plane. (Hint: Look down one of the axes.)