Algodoo

This is what we did to decide on a team.
Rule is, the 1-7 round is Group Stage.
The marbles are scored according to the results of the game. At this point, this score is all differential. After all seven rounds, you will survive from first to 12th place of each group, and you will be eliminated from 14th to 25th place. Four marbles, ranking 13th in each group, are up the vothing.
You vote, two marbles survive, the other two are eliminated.
The 50 suvivor marbles go through the Elimination Round. Seven marbles are eliminated every round. At the end, there are only 10 marbles, and the fastest one is...... Winner.