Find the 1Kg stone

This game is played with minimum 3 participants or many more (recommended). 

Rule no.1 : pick one Leader

Rule no.2 : the Leader must ask the participants to find a stone or an object, in the nearby area, that weights 1 kilo (+/- 50gr or an error weight at your choice )

Rule no.3 : you need a weighting instrument or something that can measure the stones 

Each player must be quick and must be the first to bring a 1 kilo stone to the Leader of the group, in order to win the game. The player that has the least errors in weight (less than 50grams/stone brought) and brings a 1 kilo stone fastest to the Leader, wins the game. The other ones that bring a heavier or lighter stone, will get 1 penalty point each time they calculate the wrong weight. One penalty point can be equivalent with 3 pushups, 1 minute spinning around or whatever other funny penalty you can think of:)