This Activity is meant for Boy Scouts.
Decide for yourself if it is appropriate for your younger scouts or not.

8 scouts
4 cards or paper plates or sheets of paper

Thinking, communicating, problem-solving exercise.

Divide scouts into 2 groups - A and B - give a card or paper to all the A members to distinguish them from Bs.

Line them up: A B A B A B A B

The goal is to get realigned: B B B B A A A A

Rules:

1. All moves are made as a pair (two scouts move together)
2. Pairs may not rotate or turn
3. There can be no gaps in the final line-up

This can be done in 4 moves:

A B A B A B A B
A     B A B A B B A
A A B B     A B B A
A A B B B B A     A
    B B B B A A A A