A Double Tour by Gabriel Werlen & Marchand de trucs & Mindbox - BookTwo devastating nuggets of impromptu mentalism! In A Double Tour, Gabriel Werlen reveals two new effects that until now he had only shared with a few professionals. Effect 1: Ultimate Free Will You place a prediction on the table that will remain visible throughout the experience. You present three objects to a spectator and you invite him to make three choices: which object he keeps, which object he leaves on the table and which object he gives you.