Suppose you want to draw a dihedral angle A-BC-D with dynamic angle

1. Plot points A, B and C at arbitrary locations
2. Draw plane p that passes through A, B and C
3. Draw line f that passes through B and C
4. Define slider for the arbitrary angle α=Slider(0°,180°,1°)
5. Evaluate the following command D=Rotate(A,α,f)
6. Draw plane q that passes through B, C and D.
7. Bonus: Show angle between planes p and q
   • Draw perpendicular line g from D to f
   • Find intersection point F between g and f
   • Draw angle between A, D and F