Rubik

Effect

The mentalist sends an email to a viewer and asks that he not open it until the end
Once the spectator receives the email, he delivers a ruby cube of 3x3 to mix it at will. Once mixed, the mentalist asks him to choose a face and orientation of the cube.
With this impossibility of knowing the final combination of the faces, when opening the mail you will find an image of the chosen face of the cube.