The rules of the game are that a number of players form a circle and put their hands on their lap, each player takes a turn to shout Hands Hands Up, and add a number after it, this number can not be bigger than the sum of all hands present, nor can it be a negative number, all players need to shout out this number while raising their hands, one hand, or no hands up. If the number called out happens to be equal to the sum of all the hands raised, then the current player needs to put one hand behind his back, if the wrong number is called out then the game continues as usual, and the last player with a hand on his thigh is the loser. At first, my vision was to have the player put his finger up behind them. Then shout out the number while extending the hand forward. But then there was a risk of players cheating.
