A modified black and white hairdryer of the same brand are installed on a grey platform. Directed towards each other they get into a direct relation, blowing with hot air at the opponent. The circuits and the plastic cover heat up until a decision is made: Either, one breaks earlier than the other, leaving a „winner“, both break at the same time or, being equally weak, none breaks, leaving the situation in a vital draw.
I bet $10 on the black dryer. It seems meaner!