Lynx Blackboard by João Miranda
instructions download , no props and no app included
In this effect, the magician writes a prediction on a chalkboard. The performer asks any audience member to name any number, letter, word, or anything they want to predict. The magician turns the chalkboard around, and it can be seen that the prediction exactly matches the audience member's thought! 

The magician can erase and predict anything again, as many times as desired, without stooges or pre-show work.